JEREMY Corbyn has been branded “petty” and “juvenile” after he supposedly abandoned a Downing St meeting because of the presence of Chuka Umunna, a former Labour colleague who left the party to join The Independent Group.

Theresa May had invited all opposition leaders, including Mr Corbyn, the SNP’s Ian Blackford and Liberal Democrat leader Sir Vince Cable, to discuss the thinking behind her decision to ask the EU to grant a short delay to Brexit.

But when the Labour leader saw Mr Umunna was also there, he left. One source claimed Mr Corbyn remarked: “He is not a proper party leader.”

A Labour spokesman explained: “It was not the meeting that had been agreed and the terms were broken. Downing St is in such chaos that they were unable to manage their own proposed meeting.”

He added: “We are in discussions with No 10 about holding the bilateral meeting with the PM that Jeremy proposed at PMQs.”

However, Chris Leslie, a former Shadow Chancellor who, like Mr Umunna, left Labour to join TIG, tweeted: "Astonishing. Yet again @jeremycorbyn puts petty party politics before the national interest."

Mr Umunna commented: “It is really extraordinary behaviour for the Leader of the Opposition to behave in this kind of very juvenile way when the moment demands that we all step up and engage in some serious dialogue to find a way through this chaos and this mess."

Sir Vince noted: "That is rather a strange way to behave in a national crisis."

He added: “Jeremy Corbyn’s kinder, gentler politics was found wanting as he stomped out of the meeting before it began rather than breathe the same air as Chuka Umunna.”

The SNP’s Stewart Macdonald also took to social media to comment, saying: “I mean, can you imagine him at a meeting of the UN? It’s filled with objectionable governments. Would he walk out of that?”