Perspectives from Law and Political Theory: Should MPs who Resign from their Party Also Resign their Seats?

Arjun Dwesar

At the end of last month, eleven Members of Parliament (MPs) resigned from the Labour and Conservative parties because of disagreements over their parties’ policies. All of these MPs, however, continue to sit in the House of Commons and have not resigned their seats or faced by-elections. This potentially creates a phenomenon where voters vote for a candidate from a particular party only to find after the election that she has now crossed the floor and supports different policies altogether. It raises fundamental questions of the nature of political representation and the legal basis on which MPs can, and should, be held to account. This article undertakes a critical analysis of whether MPs who resign from their party should also resign from their parliamentary seats, employing concepts in political theory and constitutional law. It will be argued that although there is no basis in political philosophy or in law to support the proposition, MPs who resign from their party should also be legally required to resign their seat. If not, basic democratic principles would be undermined.   

The Backdrop to the Debate

On 18 February 2019, seven Members of Parliament (MPs) from the Labour Party – Luciana Berger, Ann Coffey, Mike Gapes, Chris Leslie, Gavin Shuker, Angela Smith and Chuka Umunna – resigned from their party and formed a political association called ‘The Independent Group’. The ‘Gang of Seven’, as they have been labelled by the media, were subsequently joined by another Labour Party MP Joan Ryan and 3 MPs from the Conservative Party, namely, Anna Soubry, Sarah Wollaston and Heidi Allen.1 A ninth Labour MP, Ian Austin, resigned from Labour on 22 February, but did not join the Independent Group, and now sits in the House of Commons as an independent MP.2 These Labour MPs had different reasons for quitting their party, though undergirding all of them is long-standing criticism of Jeremy Corbyn’s leadership of the Labour Party on issues from Brexit, to economic and defence policy to even racism within the party.3

In the wake of their resignations, there were calls from the press for the departing MPs to also resign their seats.4 Some even argued that a general election should be called as a way to correct this aberration.5 The criticisms and calls for elections did not remain within the confines of the media. Len McCluskey, leader of Britain’s second largest trade union Unite the Union, argued that “they stood as Labour MPs on a platform in the general election 18 months ago” and suggested that the votes they received were “because of a manifesto which promised to respect the 2016 referendum and take us out of Europe”, and should thus resign their seats.6 Even some of the Gang of Seven’s ex-Labour Party colleagues exhorted them to resign. Shadow Justice Secretary Richard Burgon reasoned that “they no longer have a mandate even to speak for their constituents… people elected them to be Labour MPs on a Labour Manifesto”.7 Shadow Chancellor John McDonnell, echoing his frontbench colleague, declared that “all these MPs stood on our manifesto in 2017… now they are on a different platform, so the honourable thing, the usual thing for them to do now is to stand down and fight by-elections”.8

Popular opinion, it appears, would have the Gang of Seven and their followers resign their seats. These MPs were elected on the basis, it is claimed, of their affiliation with the Labour Party and since that affiliation has ceased, they no longer have any standing to remain as MPs. However, as at the time of publication, none of the MPs have resigned. The answer to why they have not, I posit, can be explained theoretically by concepts of political representation, and practically by the law of the United Kingdom today. I shall now proceed to critically evaluate each in turn. 

The Political Theory 

At the outset, it is important to note that there are panoply of different theories of political representation through which one can analyse any given issue.9 The paradigmatic theories of political representation, however, are the ‘promissory’ and ‘trustee’ models of representation, and it is through these I will examine whether MPs should resign their seats. 

(i) Mandate Theory

The mandate/promissory theory of representation, is what political theorist Jane Mansbridge calls “the traditional model”.10 At elections, “parties or candidates make policy proposals… and citizens decide which of these proposals they want and the winning platform becomes a mandate that the government pursues”.11 Under this view of political representation, elections serve as a check on whether politicians have kept their promises. This theory could perhaps explain why George H. W. Bush lost the 1992 US Presidential Elections, or the Liberal Democrats were almost wiped out from the House of Commons in 2015.12 It can be argued that when Len McCluskey, Richard Burgon and John McDonnell demand that the Gang of Seven resign because they were elected on a mandate for the Labour Party and its manifesto, they are appealing to this idea of political representation. In his study of political representation in Britain, David Judge suggested that the Labour Party was founded by the trade unions as a party to represent the interests of the working class, as opposed to the perceived Conservative MPs who were in Parliament to protect elite vested interests. This partially explains why “Labour party activists have, throughout the party’s history, been preoccupied with the notion of the mandate” and are anxious to ensure that Parliamentary Labour Party acts in accordance with its election manifesto programme.13

However, a defender of the mandate theory of representation might hypothetically push back and argue that actually, the Gang of Seven MPs were elected in 2017 as well-known critics of the Labour Party, its leadership, and many of its policy positions.14 For example, three of the ‘Gang of Seven’ (Luciana Berger, Ann Coffey and Mike Gapes) voted against the Parliamentary Bill triggering Article 50 in February 2017, and were critics of the party’s position on Brexit, calling for a second referendum long before the last election.15 Despite this, all three were re-elected five months later in the June 2017 General Election, with their majorities increased by over 10%. Thus, if one takes the mandate view of representation to its logical conclusion, then in resigning, the Gang of Seven have actually acted in accordance with the mandate they were given to by the electorate in June 2017, that of opposing Jeremy Corbyn’s leadership and Brexit. This position is muddied, of course, by the fact that the MPs were elected not just as individuals, but individuals on a party ticket. The advent of modern party politics means that perhaps MPs are elected on the basis of party affiliation and its manifesto, and indeed MPs do vote along party lines in the House of Commons.16 Yet, at the same time, these MPs were long-standing critics of Labour Party policy, and this would have been known to their constituents at the 2017 general election. 

One can thus conclude that under the mandate view of political representation, MPs may or may not have to resign their seat when they quit their political party, depending on whether one adopts the view of the MPs being mandated as individuals or as party representatives. If the former, then not, if the latter, then there may be an arguable case that they should.

(ii) Trustee Theory

Although the Labour Party campaigned on a platform in 2017 to unconditionally respect the Brexit referendum result, the party announced on 25 February 2019 that its position had shifted – it now supported a second referendum as an alternative to a ‘no-deal’ Brexit.17 What might explain this shift? The philosopher, statesman and former MP for Bristol Edmund Burke famously declared that “when you have chosen [an MP at an election], he is not member of Bristol, but he is a member of parliament. If the local constituent… should form a hasty opinion, evidently opposite to the real good of the rest of the community, the member for that place ought to be as far, as any other, from any endeavour to give it effect”.18 Burke’s argument is that an MP is not elected to be a spokesperson for her constituents, but rather to use her own intellect, reason and judgement to act in the interests of the country as a whole, because “parliament is a deliberative assembly of one nation, with one interest, that of the whole”.19  Under this view, MPs are elected on the basis of their judgement, character and knowledge, and should not make wild promises to the electorate which would later constrain their ability to safeguard the national interest as and when developments take place. 

Operating within the realm of the mandate model of political representation, it can be argued that when an elected MP or political party deviates from their electoral platform or changes policy positions, they are merely employing their reason and judgement and fulfilling their role as trustees of the nation’s welfare. Indeed, Chuka Umunna, speaking on BBC Radio 4, stated that he quit the Labour Party because in his view he was putting the national interest over and above his (former) party’s interest.20 In that sense, what the Gang of Seven did should be a source of approbation, not derision. In resigning from their party, they can be said to be applying their judgement and reason about what is in the interests of the UK as a whole. If voters disapprove of their MPs’ judgement, they can express their view at the ballot box at the next election. Thus, if one subscribes to the trustee view of representation, the question of MPs resigning from their seats would not even arise because they are merely fulfilling their responsibility as a trustee of the nation’s welfare. 

Having considered this issue from the lens of political theory, I will now analyse the legal implications of an MP resigning from their political party.  

The Legal Position on Resignation
(i) Constitutional Conventions

The UK’s constitution operates in many instances on the basis of convention. For example, there is a convention that after every general election, the monarch invites the leader of the party with a majority in the House of Commons to form a government (or the leader of the party that can at least command the confidence of the Commons, as is the case in the present age of coalition and minority governments). As Elliott and Thomas point out, this practice is not enshrined in law.21 There is nothing to legally prevent the monarch from asking someone other than the leader of a party with the most seats in the Commons to form the government. However, there is a constitutional convention – a form of political practice – which prevents the reigning monarch from doing so. The Supreme Court recently confirmed this proposition, with the majority in R (Miller) saying that “it is well established that the courts of law cannot enforce a political convention”.22

When does something become a convention? While much criticised, the 3-stage Jennings test developed by Sir Ivor Jennings provides a useful basis on which one may judge the existence of a convention.23 The questions one asks in the Jennings test are, firstly, what precedent, if any, is there for the practice? Secondly, do those adhering to the precedent believe that they are bound to do so? Finally, one asks whether there is a good reason for the rule. Although the courts do not enforce constitutional conventions (as seen from theMillerquote above), they have however employed the Jennings test to decide whether a constitutional convention exists, such as the heir apparent’s education convention in Evans v Information Commissioner.24

The position of MPs resigning is not enshrined in any Act or piece of legislation. In fact, under a Resolution of the House of Commons of 1624, MPs are not even allowed to resign from their seats at all! The only way a seat can fall vacant is through expulsion by the House, disqualification, death, or by holding a position which is incompatible with membership of parliament. Thus, technically in order for an MP to resign from the House, she has to procedurally be granted either the Chiltern Hundreds or Manor of Northstead by the Chancellor of the Exchequer, both of which are positions that automatically debar one from sitting as an MP.25 This however does not mean that constituents have no legal recourse if they are faced with a rogue MP. The Recall of MPs Act 2015 allows constituents to petition for the recall of their MPs. According to sections 9 and 14 of the Act, constituents can trigger a by-election if 10% of the electorate in a constituency sign a petition within a time-frame of 6 weeks. 

Given that the UK’s constitutional system operates on the basis of convention, what is the precedent vis-à-vis MPs resigning from their party? Do they concomitantly also always resign from their seat? To answer this question, one might employ the Jennings test. Firstly, is there a precedent of MPs who resign from their party also resigning from their seat? In the 1970s and 1980s, when Dick Taverne and Bruce Douglas-Mann resigned from the Labour Party, they also resigned from their seats and fought by-elections. Recently, Douglas Carswell resigned his seat when he defected from the Tories to the UK Independence Party (UKIP). On the other hand, when Mr Carswell subsequently resigned from UKIP to sit as an independent he did not resign his parliamentary seat. Similarly, when he resigned from the Liberal Democrats in December 2018, Stephen Lloyd did not resign his seat, neither did Jared O’Mara or Frank Field when they resigned from Labour, nor did Quentin Davies when he quit the Conservatives for Labour back in 2007. In essence, one can find instances of precedents either way and there is no clear evidence of a consistent precedent. Instructively for the second element of the Jennings test (whether actors believe they are bound by the precedent), it appears that the MPs who did resign their seat such as Mr Taverne, Mr Douglas-Mann, et al, did so out of their own volition and not out of compulsion or obligation.26 The analysis above suggests that the second question in the Jennings test is answered in the negative. It is thus unlikely that one can say that the act of resigning one’s seat after resigning from one’s political party is a constitutional convention. 

(ii) Should MPs be Made to Legally Resign their Seats? - the Third Jennings Criteria

Since it was established at the second stage of the Jennings test that there was no convention of MPs resigning their seats upon quitting their parties, there was no need to put the issue through the final stage of the Jennings test – whether there is a reason for the convention. It has become clear from the analysis so far that MPs have no obligation either under theories of political representation or in law to resign their seat when they resign from their political party. However, should the position in law change? In other words, as the third stage of the Jennings test would have us analyse, is there a reason for having such a rule?

In Singapore, Article 46(2)(b) of the Constitution specifies that an MP’s parliamentary seat becomes vacant if the MP ceases to be a member of the political party for which she stood for at the time of election. The genesis of this provision in the Singapore Constitution was the vote of no-confidence in the Singapore government in 1961, when 13 MPs from the ruling People’s Action Party (PAP) defected to the opposition Barisan Socialis. This resulted in the PAP government surviving the no-confidence motion by a single vote.27 Similarly, in response to an increasing number of legislators defecting to rival parties, the New Zealand Parliament passed the Electoral (Integrity) Amendment Act in 2001, section 5 of which stipulates that an MP’s seat becomes vacant if she ceased to be a member of the political party on whose ticket she was elected. A replacement bill for this has been passed by the New Zealand parliament and is currently awaiting royal assent.28

Keeping the Singapore case in mind, there thus appears to be a persuasive reason for the institution of a law preventing MPs from switching political parties after elections. This is especially in democratic systems which adopt the Westminster parliamentary model of government, because the constitution of the Executive is based entirely on its ability to form a majority in the Legislature. There may arise situations where MPs resign and cross the floor en-masse, leaving the electorate with a government they did not vote for. Of course, if they are acting in the national interest (however this vague notion can be defined) then it might be consistent with at least the trustee model of representation. However, as Buchanan and Tullock have noted in their seminal publication The Calculus of Consent, each voter has a multitude of motivations when casting her vote, with high decision-making costs potentially leading to rational ignorance among voters. This may also explain why having the ability to recall MPs under the Recall of MPs Act 2015 may not be a sufficient safeguard – in practice it could be very hard to muster the requisite number of signatures within the prescribed timeframe. Given that the current Parliament has already seen fifteen MPs resign from their parties (for reasons other than party suspension/expulsion), more than enough to theoretically topple a government, and the Fixed-term Parliaments Act 2011 making it harder for general elections to be called, perhaps it may be timely for the UK to engage in a deliberative dialogue about whether it would like to follow the likes of Singapore and New Zealand in making MPs who resign from their parties also resign their seat. If not, one day the British electorate may vote in a Tory government, only to have a Labour one (or vice-versa) without having the opportunity to go to the ballot box again. Such a development would be inimical to the interests of democracy in an era of already declining electoral turnout and rising voter distrust.   


This article has sought to analyse the question of whether MPs who resign from their political parties should also resign from their seats in Parliament using the recent resignation of Labour Party MPs to form the Independent Group as a basis for the analysis. It was argued that there is no compelling reason either within the mandate or trustee theories of political representation, nor within the present UK constitutional framework for MPs to resign their seats when they resign from their political parties. However, it was posited that if this is not corrected, there is a risk within Westminster system for changes in government which have not been sanctioned by voters at the ballot box and thus, MPs who resign from their party should also be made to resign from their seats. 


1. Patrick Maguire, ‘Three Tory MPs join the Independent Group’ (NewStatesman, 20 February 2019) <>

2. Eline Schaart, ‘Ian Austin becomes 9thMP to quit UK Labour’ (Politico, 22 February 2019) <>

3. Harry Yorke ‘I sometimes don’t recognise Labour, says deputy leader’ (The Telegraph, 19 February 2019), p.4-5 (print edition)

4. Dawn Foster, ‘Are the gang of seven right to split from Labour? Our panel responds’ (The Guardian, 18 February 2019) <>

5. Sherelle Jacobs, ‘Theresa May must strangle the Independent Group at birth by calling a general election’ (The Telegraph, 21 February 2019) <>

6. Francis Elliott ‘Corbyn Loyalists mock motives of Blair Tribute Act’ (The Times, 19 February 2019), p.10 <print edition>

7. Jack Maidment ‘Labour backlash begins as Gang of Seven MPs branded traitors and told by John McDonnell to trigger by-elections’ (The Telegraph, 18 February 2019) <

8. ibid

9. See Ian Shapiro, Susan Stokes, et al. (eds.), Political Representation (Cambridge University Press 2009)

10. Jane Mansbridge, 'Rethinking Representation' [2003] 97(4) The American Political Science Review 515-528, 516

11. Adam Przeworski, et al. Elections and Representation. in Adam Przeworski, et al. (ed), Democracy, Accountability, and Representation ( Cambridge University Press 1999) 29-54, 29

12. President Bush broke a promise made during the 1988 Presidential Elections not to institute any new taxes but later did; the Liberal Democrats promised not to raise university tuition fees at the 2010 general election but later did so while in government. 

13. David Judge, Representation - Theory and Practice in Britain (Routledge 1999), 74

14. Harry Yorke ‘I sometimes don’t recognise Labour, says deputy leader’ (The Telegraph, 19 February 2019), p.4-5 (print edition)

15. Julia Rampen and Stephen Bush ‘The MPs who voted against Article 50’ (NewStatesman, 1 February 2017) <>

16. David Judge, Representation - Theory and Practice in Britain (Routledge 1999), 70

17. Jessica Elgot ‘Jeremy Corbyn: we’ll back a second referendum to stop Tory no-deal Brexit’ (The Guardian, 25 February 2019) <>

18. Edmund Burke, Political Tracts and Speeches of Edmund Burke Esq (W Whitestone 1777), 354

19. ibid

20. Chuka Umunna, ‘Any Questions?’ (BBC Radio 4, 22 February 2019), at 18:10mins <>

21. Mark Elliott and Robert Thomas, Public Law (Oxford University Press 2017), 50

22. R (Miller) v Secretary of State for Existing the European Union[2018] AC 61, at [141]

23. Elliott and Thomas, 52

24. [2012] UKUT 313 (AAC)

25. For more information and background on this constitutional convention, see The House of Commons Background Paper SN/PC/06395, 18 July 2013 <Available at:>

26. Editorial, ‘Democracy and Conscience’ (The Times, 22 February 2019), p. 29 <print edition>

27. Kevin Tan, Singapore Legal System (Singapore University Press, 2001), 115

28. Electoral (Integrity) Amendment Bill, (New Zealand Parliament) <>

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