Of all the claims from Alistair Darling's memoir [2] (£), it is his assertion that Labour went into the last election without a "credible economic policy" that is most damaging for the party. Darling all but accuses Gordon Brown of deficit denial for refusing to accept the level of cuts and tax rises needed to ensure fiscal sustainability. Christmas has come early for George Osborne.

Darling told Andrew Marr this morning: "You need a credible economic policy. It really hampered us at the election". Some would reply that a party without a credible economic policy is unfit to govern and it was notable that Darling refused to dissent when Marr suggested as much.

The former chancellor is right to argue that Labour's economic policy wasn't credible but for the wrong reasons. Rather than pandering to Conservative demands for savage cuts, the party should have offered a distincitve economic policy based on investment to stimulate growth and reduce the deficit. It should have argued for more targeted tax rises on the wealthiest in our society. The Brown government's most popular policies were the bankers' bonus tax and the 50p tax rate. It is hardly surprising that when offered a choice between Labour cuts and Tory cuts, voters decided they wanted the real thing.

In agreeing to stick to Darling's pledge to halve the deficit over four years (while replacing a cuts-tax ratio of 67:33 with one of 60:40), Ed Miliband has met the former chancellor's definition of a credible policy. But that won't stop the Tories from claiming that Labour's policy is as uncredible now as it was then.