Jeremy Corbyn can not "conceivably" win the general election for Labour in 2020 and his politics will lead to "oblivion" for the party, former cabinet minister Jack Straw has warned.
Speaking to BBC Radio 4's World at One programme on Friday, Straw said the only way Labour could win again would be to appeal to the centre ground of British politics.
"We tested the alternative proposition, which is you can gain a majority from the left to destruction at the election less than three months ago and it ended is disaster," he said.
The former Labour justice secretary also hit out at Dave Ward, the general secretary of the CWU union, who yesterday backed Corbyn for leader and described Blarites as a "virus".
Straw said: "It's a very strange virus, New Labour, this virus, so-called, made sure we had three successive victories for the Labour Party from which the trade unions and their members particularly benefited as well as the rest of the country.
"The choice for people like Mr Ward is whether they retreat into comfort zone of far left policies which will lead to oblivion or whether we accept the world as it is with a market economy, but seek through Labour's values to moderate how that market economy works to the benefit of everyone. That's what New Labour was about and it worked brilliantly."
Corybn has emerged as the surprise frontrunner in the contest. As of Friday afternoon he had the backing of 147 local Labour parties, ahead of Andy Burnham on 110, Yvette Cooper on 109 and Liz Kendall with 15.
Straw said that without Tony Blair's victory in 1997 there would be no minimum wage, extra spending on the NHS or an "astonishing improvement" in the education system.
He told the BBC that while he regarded Corbyn as a "friend" and did not want to "rubbish" him, he was worried about what would happen to Labour should the leftwinger be elected leader.
"Overall his policies are not policies which could conceivably win an election and my real worry about Jeremy is not Jeremy, but those around him who are actively supporting him," he said.
"The issue here is this we an all be hobby politicians, which is what far left groups like Socialist Workers Party who in a sense fantasise about the kind of world they would wish, or we can be really serious about gaining power.
"Whether people like it or not you can only gain power as a centre-left party in this country if you appeal to the centre as well as to the left."Suggest a correction