A leading Labour backbencher has urged the party to understand why it lost millions of voters.
Leftwinger Jon Cruddas, who is considering running for the leadership, warned that the party should be "under no illusion" about the extent of its defeat.
Labour's 29 per cent vote share in last week's General Election was its worst performance since the party's 1983 nadir under Michael Foot.
Mr Cruddas, who is popular among rank-and-file members and the unions, suggested the party needed a change of direction after the New Labour years.
He said: "We must not put ourselves down, but we cannot hide either. We have lost millions of voters, and a careful analysis of where they have gone is crucial."
Labour members are waiting to see who will join ex-Foreign Secretary David Miliband in announcing they will run for the leadership of the party. Other potential candidates include Ed Balls, Ed Miliband and Alan Milburn.