The Labour Leader is thought to have refused to sit down with the Independent Group spokesman as ‘he’s not a real party leader’.
Mr Corbyn was labelled ‘juvenile’ after refusing to join the cross-party meeting and has been slammed online for his behaviour.
Countdown presenter Rachel Riley mocked Mr Corbyn for meeting with Hamas – the military wing of which is a banned terrorist group in the UK – but failing to talk with Mr Umunna.
Jeremy Corbyn reportedly walked out on a crucial Brexit briefing with party leaders because former Labour MP Chuka Umunna (left) was invited
The move has been criticised online, with Countdown presenter Rachel Riley commenting on the matter on Twitter
She wrote on Twitter: ‘Corbyn on Hamas (the terrorists): I wanted Hamas to be part of the debate.
‘Corbyn on Chuka Umunna (the anti-racism ex-Labour MP): Tell him I’m not talking to him. OK, got it.’
Mr Umunna, who is not officially the leader of the newly formed Independent Group but instead an appointed ‘spokesman’, said: ‘We are in a crisis situation here where the people of this country expect their representatives from different political groupings in Parliament to come together and actually chart a way forward.
‘That is why the Prime Minister convened the meeting, I welcomed the fact that she did so.
‘I think it is really extraordinary behaviour for the leader of the opposition to behave in really 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.
‘He will have to explain his actions.’
Speaking after the meeting, Liberal Democrat leader Sir Vince Cable said: ‘That is rather a strange way to behave in a national crisis.’
A Labour spokesperson said: ‘It was not the meeting that had been agreed and the terms were broken. Downing Street is in such chaos that they were unable to manage their own proposed meeting.
They added: ‘We are in discussions with Number 10 about holding the bilateral meeting with the PM that Jeremy proposed at PMQs,’ according to The Mirror.