Dave Ward Communications Workers Union
Dave Ward, head of the Communications Workers Union, has defended describing Labour right-wingers as a "Blairite virus"Getty

The chief of the Communications Workers Union, Dave Ward, has defended describing Labour right-wingers as a "Blairite virus" after leadership hopeful Liz Kendall criticised the language as offensive. Ward made the remark when his union, which has more than 220,000 members, backed Jeremy Corbyn in the Labour leadership contest. The general secretary claimed that Corbyn would be an "antidote" to the politics pushed by the likes of New Labour co-architect Lord Peter Mandelson.

Kendall, who is seen as the Blairite candidate in the leadership contest, last night (30 July) told the BBC's Newsnight that Labour "need an antidote to the Tories" and criticised Ward's comment for being offensive. But the union chief was unrepentant this morning when he spoke on BBC Radio 4's Today Programme. Ward stuck by the "virus" description and claimed that Labour had lost its core values and "adopted market values".

He also argued that Labour should not compromise its principles "just in pursuit of an election victory", saying that the leadership contest was an opportunity for the party to have a "fundamental debate" about what it stands for. Ward conceded that Labour, under Tony Blair and later Gordon Brown, had made some good moves but claimed Blairites "never accept any of the bad things they've done".

The comments come after Unison, the public sector union, also threw its support behind Corbyn. Dave Prentis, the general secretary of Unison, which represents more than 1.2 million workers, said: "Corbyn's message has resonated with public sector workers who have suffered years of pay freezes and redundancies with too many having to work more for less. Their choice shows a clear need for change towards a fairer society where work is fairly rewarded, and where those living and working in poverty are supported."

The union also selected Yvette Cooper as its second preference. The latest polls show that Corbyn is storming ahead in the leadership race. A private survey, seen by The Daily Mirror, put the socialist firebrand on a 20 point lead over Cooper. A separate poll by YouGov, which was commissioned by The Times, put the left-winger 17 points ahead of Burnham.

Burnham and Cooper are now battling to become the so called "anything but Corbyn" candidate in a bid to stop the socialist from becoming Ed Miliband's successor. Kendall meanwhile, has trailed in the opinion polls. Labour will sent out ballot papers on 14 August and the new leader of the party will be announced at a special conference on 12 September.