There could be a seventh candidate in the Labour leadership contest – shadow international trade secretary Barry Gardiner.
The Brent North MP, who has developed a following on the left of the party for his defence of Jeremy Corbyn’s policies, has said he is “considering it at present”.
Such a move could damage support for shadow business secretary Rebecca Long-Bailey who has tried to position herself as the candidate for Jeremy Corbyn supporters.
Unite union boss Len McCluskey denied reports that he was trying to get Gardiner to declare for the contest.
Gardiner held government roles under Tony Blair and Gordon Brown, voted for the Iraq War in 2003 and backed David Miliband as Labour leader in 2010.
Speaking to the Daily Mirror, he said: “At the moment I am still considering it and I’m going to try and make a decision as soon as I possibly can.
“I’ve got to speak with some more people.
“It’s really a matter of I want to heal the division in our country, I want to help people have a better life in a fairer Britain, it’s as simple as that really.”
Would-be candidates have until Monday to secure backing to make it into the second round of the battle which will see the new leader announced on April 4.
Sir KeirStarmer was the first to receive the backing of enough Labour MPs to enter the second round.