TODAY is a huge day in the lengthy Brexit process. We already know that Theresa May's deal is likely to suffer a humiliating defeat, what we don't know is exactly what will happen once it is defeated.

That will become clearer in the coming days. For now, MPs are preparing to debate and vote on amendments ahead of the so-called meaningful vote this evening.

READ MORE: Brexit Vote Live: May braced for crushing defeat in Commons

With that in mind, here is what some key figures are tweeting ahead of a crucial afternoon in British politics.

We kick off with the SNP's leader at Westminster Ian Blackford, who has reiterated that the SNP will vote against May’s deal.

His deputy, Kirsty Blackman, has shared the video she recorded for the BBC which argues that the deal is something people “don’t actually want”.

Next we have the leader of the official opposition, though you’d be forgiven for not knowing that they are. Jeremy Corbyn says the Prime Minister will only have herself to blame when the deal is defeated.

Scottish Tory MP Ross Thomson has also had his say and claims that May's deal is "the biggest threat to the Union since #IndyRef".

His colleague Jacob Rees-Mogg wants to see the deal defeated, but not because he wants a better one, because he wants to go off a cliff edge.

Meanwhile the leader of the DUP, who were paid to prop up this minority Tory government, Arlene Foster said that tonight will be “historic but for the wrong reasons” and labels the backstop "toxic".

And their party leader at Westminster, Nigel Dodds, predictably, also focuses on the backstop.

LibDem (remeber them?) leader Vince Cable points out that May is not only facing defeat, she lacks a plan B.

The Plaid Wood leader Leanne Wood focuses on the Tory hypocrisy when it comes to referendums.

And their leader at Westminster, Liz Saville Roberts, shares a video in which she challenged the Prime Minister on the issue.

Green MP Caroline Lucas explains why she will be voting agains the deal.

Elsewhere, SNP MP Gavin Newlands changes the tone a little with a sarcastic swipe at the Daily Express front page from this morning.

Finally, Christina McKelvie focuses on something slightly different though related given the timing of the announcement.