Labour lords open a new front in the Brexit battle

The story so far - this week the government's bill to trigger the process of leaving the EU cleared Parliament un-amended.

But the government did give MPs and peers assurances on two key issues.

First: that sorting out the status of EU nationals living in the UK (and of Brits resident in the EU) was an immediate negotiating priority.

Second: that there would be a vote in Parliament - the so-called meaningful vote - on the ultimate divorce deal.

The Brexit Secretary, David Davis, told the Commons on Monday that the government had made a commitment to "bring forward a motion on the final agreement to be approved by both Houses of Parliament before it is concluded....We expect and intend that this will happen before the European parliament debates and votes on the final issue.....Our clear intention, an intention stated more than once at this Dispatch box, and by far the most likely outcome, by the way, is that we will bring back a deal to the Houses of Parliament for them to approve."

Much of the Brexit manoeuvring in Parliament now revolves around how this final vote would actually work, particularly in the scenario where the divorce talks fail, and Britain leaves the EU with no special agreement and has to trade with its partners on the World Trade Organisation terms.

If there's no deal, is there still a vote? Or is it automatic exit on WTO terms?

The Labour Lords have now given notice of a motion which will probably be debated in the next couple of weeks:

"Baroness of Smith of Basildon [the shadow Leader of the House] to move that it is expedient that a Joint Committee of Lords and Commons be appointed to consider and report on the terms and options for any votes in Parliament on the outcome of the negotiations on the UK's withdrawal from the European Union, including how any such vote be taken before any agreement is considered by the European Parliament; and that the committee do report by 31 October 2017."

Lady Smith, who is arguably the most powerful Labour parliamentarian, flatly denies that this motion is a Trojan Horse for the Remain cause, designed to create an opportunity for a last ditch parliamentary vote to stay in the EU.

But she does argue that if the government were to oppose her, it would cast doubt on the sincerity of their promises about parliamentary sovereignty.

In fact, it gives ministers an awkward choice between resisting what would probably be a Lords majority for the plan, and acquiescing to a committee of great and good peers, building what they would doubtless see as elephant traps into the final furlong of Brexit.

There's also a second motion calling for a report before the end of the current parliamentary year (a moveable feast, but probably around 10 May) setting out the progress on the EU nationals/expat Brits issue - another chance for ministers to have their feet held to the fire.

Key crossbench peers have already been consulted, and the Liberal Democrat peers would find it hard not to support this proposal - and it would also provide Labour with useful points as the Lib Dems continue to pitch themselves as the party of Remain while painting Labour as appeasers in the Brexit battle.

Just when you might have expected a lull in Parliament's Brexit battles, the Labour lords have opened a new front.