David Miliband is taking his Labour leadership bid on the road as he seeks to gain an early advantage in the race to succeed Gordon Brown.
The former foreign secretary was the first to announce he was running for the job, declaring his candidacy on Wednesday evening, within 24 hours of Mr Brown's resignation.
He will set out on a "conversation" tour of the UK to find out from voters why they turned away from Labour in their millions in last Thursday's general election.
There is fevered anticipation at Westminster that his brother Ed Miliband, as well as Ed Balls and Andy Burnham, are on the verge of announcing their own bids.
Another challenge could come from popular backbencher Jon Cruddas, who last night addressed Labour activists in Westminster as he weighed his options.
In a forceful intervention in the debate about Labour's future, Mr Cruddas urged the party to look to its record in office to understand why it had alienated some of its core supporters.
He said Labour should be "under no illusion" about the extent of its defeat, its 29 per cent vote share last Thursday representing its worst performance since the party's 1983 nadir under Michael Foot.