Jon Cruddas has outlined some "hard truths", as the former policy chief put it, to his party. An independent investigation led by the Dagenham and Rainham MP found the British electorate turned their backs on Labour at the general election because of the party's "austerity-lite" stance. The voters, according to Cruddas's probe, were drawn to George Osborne and the Conservatives as they promised to tackle the UK's deficit.

The former policy co-ordinator's survey found more than half of respondents (58%) agreed with the statement "we must live within our means so cutting the deficit is the top priority" and only 16% of voters disagreed with it.

"The Tories won because voters believed they will cut the deficit, even though a majority understand that the economic system is unfair. The Tories' message on the deficit was clear, Labour's was not. The Tories are trusted to manage the country's finances, Labour is not," Cruddas wrote for LabourList.

The MP's other "hard truth" for his party is that the idea of an alliance between Labour and the SNP turned voters off, despite Ed Miliband promising to not form a coalition government with the nationalists ahead of the election. Cruddas's survey found 60% of English and Welsh voters agreed they "would very concerned if the SNP were ever in government", with only 15% disagreeing.

The research is not endorsed by or connected with the party and Margaret Beckett, a Labour grandee, is leading the party's official "learning the lessons" taskforce, but Cruddas' independent study comes at a crucial time for the reds. Jeremy Corbyn, the socialist Islington North MP, is set to become the party's next leader and the left-winger espouses an anti-austerity agenda.

The veteran parliamentarian is facing competition from Andy Burnham, Yvette Cooper and Liz Kendall to become Ed Miliband's successor. But the last independent poll, commissioned by The Times and conducted by YouGov, put Corbyn 17 points ahead of Burnham.

A separate private poll, which was leaked to The Daily Mirror, put the 66-year-old a staggering 20 points ahead of Cooper. But, with second preference votes in consideration, the former work and pensions secretary is only two points behind Corbyn (49% vs 51%, respectively).