Shadow international trade secretary Barry Gardiner has claimed fellow MP Chuka Umunna only helped to form the Independent Group because “he knew he could never be the leader of the Labour Party”.

The show cabinet member also cast doubt on antisemitism as a primary motivation for most of the defecting Labour MPs.

Several of the eight opposition MPs who announced earlier this week they were joining a new independent collective cited the party’s failure to tackle antisemitic abuse as a key reasons for quitting.

Mr Gardiner said he was “deeply saddened” that one of the MPs, Luciana Berger, felt she had to leave over the harassment she suffered in her constituency.

“I have no time for the others at all, because actually their reasons are varied but different,” he told Sky News’s Ridge on Sunday.

“What I’m clear about is that I don’t believe that [antisemitism] is the sole focus of why they’ve left the Labour Party.”

Which MPs defected to form Change UK? Show all 12 1 /12 Which MPs defected to form Change UK? Which MPs defected to form Change UK? Change UK Details on the individual MPs are in the following photos Reuters Which MPs defected to form Change UK? Heidi Allen Anti-Brexit MP for South Cambridgeshire resigned from the Conservative party on February 20 PA Which MPs defected to form Change UK? Chuka Umunna MP for Streatham since 2010 and prominent People's Vote supporter PA Which MPs defected to form Change UK? Anna Soubry The prominent anti-Brexit MP for Broxtowe resigned from the Conservative party on February 20 PA Which MPs defected to form Change UK? Luciana Berger MP for Liverpool Wavertree since 2010, resigned from the Labour Party over bullying and anti-semitism PA Which MPs defected to form Change UK? Sarah Wollaston Anti-Brexit MP for Totnes resigned from the Conservative party on February 20 PA Which MPs defected to form Change UK? Joan Ryan MP for Enfield North resigned from the Labour party on February 19 citing its tolerance of a "culture of anti-Jewish racism" PA Which MPs defected to form Change UK? Ann Coffey MP for Stockport since 1992 Chris McAndrew / UK Parliament Which MPs defected to form Change UK? Gavin Shuker MP for Luton South since 2010 Getty Which MPs defected to form Change UK? Chris Leslie MP for Nottingham East since 2010 PA Which MPs defected to form Change UK? Mike Gapes MP for Ilford South since 1992 PA Which MPs defected to form Change UK? Angela Smith MP for Penistone and Stocksbridge since 2010

The MP for Brent North accused Mr Umunna, one of the leading figures in the new collective of breakaway MPs, of being motivated by frustrated personal ambitions inside Labour.

“It was fairly clear to me that in effect the reason he wanted to leave the Labour Party was he knew he could never be the leader of the Labour Party,” he said.

The Labour spokesman also said only a small number of Labour members were guilty of antisemitism.

“We’re talking about a very tiny minority in the party that are causing huge distress by the appalling way in which they are behaving,” said Mr Gardiner.

Antisemitism not 'sole focus' of former Labour MPs who joined Independent Group, shadow cabinet member Barry Gardiner says

The frontbencher claimed 61 members of the party had been expelled or had quit in the process of disciplinary investigation into antisemitism over the past 18 months.

“We have changed the way in which we deal with them to deal with them faster, we weren’t dealing with them fast enough,” he added.

Earlier on Sunday, however, Labour’s deputy leader Tom Watson said the party still had more work to do to stamp out antisemitism and revealed he had passed on 50 cases of abuse to leader Jeremy Corbyn this week alone.

“Jeremy needs to understand that to be in No 10 he needs to change the Labour Party. We have got to eradicate antisemitism, anti-Jewish racism in all its forms.”

“This week I have had 50 complaints of antisemitism from my party colleagues which I shared with Jeremy. I think he needs to take a personal lead on examining those cases and, if necessary, recommend to our NEC what has to be done.”