Westminster is gripped by the latest round of power struggles over Brexit. Following a historic defeat, losing by a record 230 votes two weeks ago, the Prime Minister will return with her motion to Parliament tomorrow, but this time it is facing a series of amendments.

Any one of them could help break the deadlock and move things on, but there is a real possibility that none of them will get passed and we will still be deadlocked as the clock ticks down to Brexit on March 29.

There are two main options, from different sides of the Brexit divide.

An amendment proposed by Labour's Yvette Cooper and Tory MP Nick Boles focuses on extending Article 50 by up to nine months to avoid leaving the European Union with No Deal.

The SNP and Lib Dems will support this amendment but the key to getting enough Parliamentary support is whether the Labour leadership backs it.

There has also been some talk of government ministers resigning to vote for this option, but I wouldn't hold my breath on that.

The second big amendment, which seems to be gaining ground, comes from Conservative MP Sir Graham Brady.

He chairs the backbench 1922 Committee of Conservative MPs and is a big Brexit supporter. It, in theory, backs the Prime Minister's plan, except for the Northern Irish backstop.

It aims to strengthen Theresa May's hand in going back to Brussels and demanding a better deal. It has been gaining support among the hard Brexiteers, who now seem willing to back the PM's deal without the Irish backstop.

If the government and the DUP back it, it has a real chance of success, but beyond Westminster it would mean serious renegotiation with Brussels and they and the Irish government are ruling it out.

The SNP will propose revoking Article 50 to hold another referendum, the so-called People's Vote.

Former Conservative Attorney General Dominic Grieve is proposing an option to return power to Parliament. This would give much more control over the parliamentary timetable to MPs voting on different proposals.

Hilary Benn's option involves holding a series of indicative votes until MPs find one which can carry a majority in Parliament.

Labour MPs will meet today to finalise their plans. Jeremy Corbyn is clear that No Deal must be taken off the table, beyond that he is less clear. His amendment is likely to focus on that and remaining in a Customs Union.

Another cross-party amendment comes from Labour MP Jack Dromey and Conservative MP Caroline Spelman calling on the PM to rule out a No-Deal Brexit, but does not bind her to it. Obviously the government would rather that went through than the Cooper/Boles amendment.

Before that, though, Labour MPs meet this afternoon and the Cabinet meets tomorrow morning, but the real power, here, lies with the Speaker, John Bercow. He will select which amendments will be voted on in the Commons on Tuesday.

These votes could change everything, or nothing.