The House of Commons returns to work today. So, what has changed after the Christmas break with regards to Brexit? Nothing, save for the fact that we are just 11 weeks away the theoretical departure day yet none the wiser as to how we would leave the European Union or whether we will leave at all.

We cannot carry on with this gridlock while the clock ticks down to the potential disaster of no deal. Parliament must not allow it – now is the time for the UK’s legislature to assert itself like never before.

As it happens, it is in the prime minister’s interest for parliament to seize the initiative in this way. Whereas the government or an insurgent opposition is usually the controlling mind in the Commons, neither frontbench is currently in control of events.

I saw this for myself when ministers capitulated to the demand Anna Soubry and I made through our amendment to the Finance Bill, forcing the government to publish economic impact assessments comparing the various Brexit scenarios against the baseline of EU membership.

MPs expect ministers to make more such concessions to avoid being defeated on legislation in the coming weeks.

So what happens next? First, the government must not be allowed to delay any further in holding the “meaningful vote” on her withdrawal agreement with the EU, originally planned for the week of 10 December before the break.

The PM said on the BBC’s Andrew Marr Showyesterday that the vote will definitely go ahead next week, on 14 or 15 January. But there is no time to waste, she should hold the vote immediately. The concern is it still might not happen as promised.

In any event, MPs have a variety of parliamentary tools at our disposal to illustrate the view of the Commons on the withdrawal agreement. If we don’t get the vote, working from the backbenches and cross party, be in no doubt – we will use these tools if she seeks to dodge it.

If May delivers on her promise to hold the meaningful vote and is defeated – as we all expect – there has been a suggestion that the government will simply seek to run down the clock and bring her agreement back to the Commons again and again until it is approved.  

May was asked several times on Marr whether this was her intention and she failed to categorically rule it out. According to Erskine May (the guide book on the rather archaic rules which govern how the Commons works) she shouldn’t be able to do it anyway:

“A motion or an amendment which is the same, in substance, as a question which has been decided during a session may not be brought forward again during that same session.”

The speaker of the house would be left to decide if some underhand semantics sought to sidestep that rule.

Therefore, unless the PM secures substantial and material changes to the withdrawal agreement, the government will very likely be barred from repeatedly putting the same motion to approve the same agreement.

But what if, having failed to secure Commons approval of her agreement, May announces she is to pave the way for our exit from the EU without a deal? The impact of no deal has been neatly summarised by the independent House of Commons Library here – higher trade barriers, delays caused by customs checks of trucks from the EU potentially causing a 17-mile queues at the port of Dover, a hard Irish border, possible food shortages and so on.

We have a public duty to stop this disaster. There is a majority against a no-deal Brexit in the country and in the Commons but how, legally, can such a scenario be stopped?

Domestically, the exit date of 29 March would have to be changed in law. For this to happen it is unclear whether a vote of the Commons will be needed but it almost certainly will need the government to act.

More than 200 MPs from across the Commons wrote to May today asking her to rule out no deal. The challenge is that she has already made it clear she will not do so. Also, one thing that did happen during the Christmas period is that Whitehall stepped up its planning for no deal on her instructions.

Several Ministers have said privately that they will resign if the PM follows this course. Their resignations may reduce what little is left of the PM’s authority, but they will not stop the ticking clock in law – it will not force her legally to act.

When it comes to forcing the government’s hand, political declarations, non-legally binding motions, symbolic resignations and letters simply will not work. The usual political rules that precipitate action do not seem to apply because if they did May would have ceased being PM months ago.

For example, she was defeated three times in votes on a single day before Christmas, an extraordinary event, and carried on regardless afterwards. If MPs want to change the trajectory we are on, we will need to act with legal teeth.

So those of us who have been working cross party to avoid this scenario are going to use guerrilla tactics in the Commons to prevent it from happening – we will start by using the Finance Bill again, which returns to the House tomorrow.

Two cross-party, backbench amendments to the Bill (which implements the Budget) are swiftly gaining support across all sides. Amongst other things, the Bill seeks to give ministers special powers to change the tax system to address the scenario of no deal.

My Labour colleagues Yvette Cooper and Chris Leslie have put down amendments to make the exercise of these powers subject to parliamentary approval. I have added my name to both amendments – Chris’ amendment already has over 40 MPs on it. Both will almost certainly be supported by the opposition front bench and gain enough Tory rebels to be able to carry. The same coalition of MPs could then refuse to allow ministers to exercise these Finance Bill powers if the PM pursues no deal.

This, the government cannot ignore. We will employ these kinds of tactics on all legislation from hereon in.

The other side of the coin is the need, at an EU level, to secure an extension to the Article 50 process. The EU has been clear: an extension of the Article 50 process for a democratic vote, yes; an extension for more negotiation, no.

We may not currently have enough MPs that would vote for a People’s Vote to make it a reality but once the PM’s agreement falls, there is all to play for – we believe we could secure the numbers if the opposition whipped its MPs to back it.

Uncommitted colleagues on all sides of the Commons who are sympathetic but have misgivings about a Final Say referendum do at least believe a no-deal Brexit must be avoided. The Commons resolving to hold a new public vote really is now the principal way to avoid jumping off that cliff – this is the reality as parliament resumes today.