Alban Maginness: Corbyn's five-point plan is Trojan horse to cause fatal split in Tories
Labour leader's appeal to the 'national interest' would cross one of the PM's infamous red lines, says Alban Maginness
Jeremy Corbyn's letter on the Brexit stalemate last Wednesday to Prime Minister Theresa May could well be a game-changer. As the countdown to Brexit inexorably continues and the departure date nears without even the semblance of a deal, the last real chance of achieving a House of Commons majority on the terms of a deal has been opened up by the Labour leader.
In that letter he outlined Labour's position on Brexit. In essence he wrote that the party wanted the UK to remain fully within the customs union and aspects of the single market. There are other issues that he has highlighted, such as workers' rights and security, but they are, in real terms, already within the scope of the Prime Minister's deal on Brexit.
While, on the face of it, this letter may be seen as Labour acting in a conciliatory and flexible fashion, apparently attempting to protect the UK's national interest, it is also designed as a Trojan horse to fundamentally split the Conservative Party.
If May accepts the basic substance of Corbyn's conditions - that is, permanent membership of the customs union - then she will be breaching one of her infamous "red lines" and will be moving towards a much softer Brexit.
This will in turn antagonise the hard Brexiteers like Jacob Rees-Mogg and the European Research Group.
The ultimate question for the Prime Minister is whether it is more desirable to achieve a pragmatic, deliverable deal with Labour in the national interest of the UK, or should she put her Conservative Party first and protect its political unity.
This will be the great dilemma for May - if she is able to reach a deal with Corbyn on Europe.
For the moment, at least, she has responded positively to the letter with a surprising flexibility and has not explicitly rejected any of its five demands, including membership of the customs union. She has simply indicated that she wishes to engage further on Labour's position.
The fact that she has not rejected Labour's demands will inevitably lead to anxiety, with her hard Brexiteers fearing that she will sell them short.
But the problem for them is if May does not produce a deal by the end of March, a no-deal Brexit is inevitable and that will be disastrous for the country. Would they, in particular, wish to bear the huge responsibility for plunging Britain into such a calamity?
But Corbyn's letter has also brought about a hostile reaction within a very divided Labour Party at Westminster. There is a sizeable number of his MPs who see Corbyn's letter as writing off the idea of a second referendum, which they believe could reverse the folly of the original 2016 result.
As agreed at its last party conference, Labour's current policy is to seek another referendum, when all other options have been exhausted.
The Corbyn leadership had to be dragged kicking and screaming to agree to this policy.
Several Remainer Labour MPs strongly argue that this point of exhaustion has already been reached and that Corbyn's letter is an attempt to sabotage the staging of a second vote.
Pro-Remain Labour MPs view Corbyn with great suspicion on this issue and, rightly, suspect him as being at heart a Eurosceptic.
This will continue to be a problem for Corbyn, for if he does reach an agreement with May based on his five demands, it is likely many pro-Remain Labour MPs would not support such a deal in a vote in the House of Commons. So, while Corbyn might split the Conservatives, he also runs the risk of splitting his own uncertain and divided party at Westminster.
The reaction in Brussels to the Labour leader's overtures to May has been positive and has been welcomed by Guy Verhofstad, the European Parliament's top man in relation to Brexit.
He said: "Cross-party co-opertion is the way forward and we welcome Jeremy Corbyn's letter to Theresa May to offer a cross-party exit."
As the Father of the European Parliament, German Christian Democrat Elmar Brok wittily remarked: "London must speak to London."
He and other European parliamentarians are baffled by the continued failure of the British Parliament to reach a cross-party consensus on the terms of a Brexit deal. This is why Corbyn's initiative has come as a relief to them.
If May compromises and does a deal with Corbyn that includes staying in the customs union, it would undoubtedly be approved by Brussels - not least because it would ease considerably the problems over the backstop and the Irish border.
But whether the DUP would support May in such a deal is questionable, given Nigel Dodds' derisive response to Corbyn's letter.
Meanwhile, the clock continues to tick.