Brexit terms and the Commons – a quick back of the envelope calc

Labour's new shadow Brexit Secretary Keir Starmer has today called for the House of Commons to vote on the opening terms for negotiating Britain's departure from the European Union. The Prime Minister has ruled this out. However, Ed Miliband has reportedly had talks with Conservative MPs who believe that Parliament should have more of a say. The Observer's Toby Helm has suggested that this could prevent 'Hard Brexit' and the departure of Britain from the Single Market.

Are there enough MPs willing to force a vote on the terms? Below is a quick first look at the numbers. I will try and update it as developments unfold.

New Post – 6 December 2016. Update ahead of Labour's opposition day debate.

Current state of the parties at Westminster

Conservative 329
Labour 230
Scottish National Party 54
Democratic Unionist Party 8
Liberal Democrat 8
Independent 4
Sinn Fein 4
Plaid Cymru 3
Social Democratic & Labour Party 3
Ulster Unionist Party 2
Green Party 1
Speaker 1
UK Independence Party 1
Vacant 2
Total number of seats 650
Working Government Majority 16 (parliament.uk)

Now lets divide those parties according to their likely willingness to support a Commons vote on the Brexit terms:

Parties likely to support a Commons vote on Brexit.
Labour 230
Scottish National Party 54
Liberal Democrat 8
Plaid Cymru 3
Social Democratic & Labour Party 3
Green Party 1
Natalie McGarry 1- 'Yes. The "hard Brexit" being postured is not what was offered. Parliament must be able to review terms.' Twitter – 10 Oct 16.
Michelle Thomson.

total 301

Parties likely to oppose a commons vote on Brexit.
Conservative 329
Democratic Unionist Party? 8
UK Independence Party? 1
total 338

Parties uncertain
Independent 2 -Simon Danczuk, Lady Hermon.
Ulster Unionist Party 2

MPs unlikely to vote
Sinn Fein 4
Speaker 1
Vacant 2

This gives us a notional Government majority of 37, so that the opposition would need around 38 government absentions or 19 switchers or a combination of both to win.

Potential Government rebels

1. Anna Soubry- 'Growing x party support for Parliament to shape #Brexit & manifesto commitments to #SingleMarket membership.' Twitter, 8 Oct 16.
2. Nicky Morgan - @SophyRidgeSky: 'Nicky Morgan says "given the Brexit vote was about sovereignty," it would be "extraordinary" for Parliament not to have its say #murnaghan'. Twitter, 8 Oct 16.
3. Nick Herbert – 'The question is not whether we leave the EU but on what terms. Conservatives must beware Brexit fundamentalism'. Guardian, 2 Oct 16.
4. Ken Clarke – Wrote to a constituent that he would vote against triggering Article 50 if there was a Commons vote. Guardian, 13 September 16.
5. Dominic Grieve – 'We undoubtedly need a vote in Parliament. It is a matter of convention.' Independent, 17 July 2016.
6. George Osborne – 'Brexit won a majority. Hard Brexit did not.' Guardian, 23 September 2016.
7. Neil Carmichael: "We would be reckless if we did not challenge some of the consequences of a hard, or harsh, Brexit." Independent, 2 October 16.
8. Stephen Phillips – The Government has 'no authority or mandate to adopt a negotiating position without reference to the wishes of the house', Guardian, 10 Oct 16.
9. Alistair Burt. ''It is one thing to come to Parliament and be engaged and tell Parliament what the Government are doing. It is quite another to come and be engaged and influenced by Parliament on things that we still need to clarify.'' Hansard, 10 Oct 16.
10. Nicholas Soames.
11. Andrew Tyrie.
12. Ben Howlett.
13. Claire Perry – 'The problem that the Secretary of State is not acknowledging is that many people in this country do not think that there is a policy to put the national interest first; they think that there is a policy to put people’s narrow ideological interests first.' Hansard, 12 Oct 16.
14. Jeremy Lefroy – ' In addition to agreeing with the right hon. Member for East Ham and other hon. Members about having the fullest possible access and, if possible, being part of the single market, I will mention two points from my long experience of selling into the EU from outside it over more than two decades.' Hansard, 12 Oct 16.
15. Sarah Wollaston.

Potential Opposition rebels

It's possible that some of the small number of MPs who supported Brexit might oppose a Commons vote on the terms.