For a man of the people, donning the garb of a knight in shining armour should be an uncomfortable experience for Jeremy Corbyn, leader of the Labour party. Yet it is a role he will relish as meets Michel Barnier, the EU chief Brexit negotiator, Antonio Tajani, president of the European Parliament and other EU big-hitters in Brussels today.

Timing is all in politics and Mr Corbyn’s is impeccable. The meeting will take place ahead of the Prime Minister’s much-touted summit that starts today, also in Brussels, and seeks to break the deadlock on the EU’s three big demands: the Brexit divorce bill, guaranteeing citizens’ rights and the Irish border question.

Mrs May seeks to make progress on the second point of contention by writing in an open letter to EU citizens that she wants to make it as easy as possible for them to secure settled status in the UK. Judging by the comments from Donald Tusk, the European Council president, last night, the Brussels mood music is sombre.

He does not expect progress before the next scheduled meeting of EU leaders in December and, to make matters worse for the Prime Minister, Mr Corbyn portrays himself as the man who can help take the talks forward and “break the Brussels logjam”.

Thanks, Jezza, the Prime Minister will not say. Mr Corbyn’s armour should be uncomfortable for another reason: his party is not as riven as the Tories on Brexit but but Labour is not a shining example of unity on the terms of an EU exit or, indeed, if there should be a divorce at all. Labour will argue, with some justification, that this is a minor quibble compared with offering to help sort out the mess the Government is making of the process.

It was apparently at Mr Corbyn’s behest that the meeting with Mr Barnier will take place. That is not so bad for Mrs May as it would have been had the EU’s Brexit boss man the source of the request. But the circumstances still look bad for the Prime Minister. For Mr Barnier to agree to meet the leader of the UK Opposition hours before talks with the British premier suggests, to put it mildly, that the EU’s chief negotiator is somewhat lacking in respect for Mrs May.

She is desperate to move on to talking about a trade and transition deal, mindful of the cracks in her cabinet that progress in an area vital to the country’s economic wellbeing could paper over, if only temporarily.

But all the signs are that the 27 EU leaders will tomorrow block any prospect of this due to the lack of progress on the divorce bill and the Irish border. Even Mrs May’s seemingly conciliatory tone on citizens’ rights could receive a cool reception, bearing in mind the hardball on the part of Mr Barnier and his colleagues.

It is all shaping up to be a day trip to forget for the Prime Minister. The journey home will be particularly tiresome if Mr Corbyn, having managed to steal a march on Mrs May, is able to make an impression on Mr Barnier as a man with a plan that could work. First, of course, he would have to be Prime Minister.