Jeremy Corbyn's campaign team has welcomed comments by Gordon Brown that the Labour party must become "credible, radical and electable", and insisted this means that their candidate is the right man to lead the party.
Brown avoided naming any of the Labour leadership candidates in his speech on Sunday, but in what appeared to be a veiled reference to Corbyn, he said:
Brown's comments would appear not to be an endorsement of the veteran left-wing candidate, in fact he appeared to suggest electing Corbyn would leave Labour powerless.
Nonetheless Corbyn's team said he was the most likely to engage with voters beyond Labour's existing supporters.
A spokesman for the Corbyn's campaign: "Gordon Brown has highlighted the need for a Labour party that stands for hope: that is credible, radical and electable - on which basis the best candidate to vote for is Jeremy Corbyn.
"...It is necessary to be credible but credibility cannot mean an orthodoxy of austerity that chokes off recovery – instead we need a Labour party that stands for growth, investment and innovation across the whole country."
Watch ITV News political correspondent Libby Wiener's report on Gordon Brown's speech:
Separately, Yvette Cooper's campaign claimed internal polling shows only she will be able to defeat Corbyn for the party's leadership.
Liam Byrne, a former cabinet minister said that internal polling showed she was "clearly on course to beat Jeremy in the final round" of voting and appealed for backers of rival candidates to offer her their second preferences.
The campaign said a blind calling phone survey of 782 people found Mr Corbyn was clearly in the lead - with 38% - but Ms Cooper was on 18%, Mr Burnham on 15% and Liz Kendall on 8%.