Bookmakers are shortening the odds on London MP Jon Cruddas becoming the next Labour deputy leader amid signs that he has strong constituency support.
Ladbrokes, which has said the Dagenham MP is "creeping up on the rails", has trimmed his odds from 8/1 to 6/1.
The move, which makes him third favourite after international development secretary Hilary Benn and education secretary Alan Johnson, suggests the only challenger from outside the government is continuing to put in a strong performance.
The left-winger is confounding expectations that his low-profile would leave him trailing the ministerial big-hitters.
But his freedom from collective government responsibility appears to have freed him up to run the boldest campaign, targeting the grassroots without the baggage of office the other candidates carry.
The news comes as the latest Labour figures show that Cruddas has the second largest number of constituency Labour Party pledges, again trailing behind Benn.
The international development secretary had received pledges of support from 77 constituency parties by the time nominations closed on Friday.
Just nine behind, Cruddas gained the support of 68 local organisations with justice minister Harriet Harman on 60, education secretary Alan Johnson on 45, Labour chairman Hazel Blears on 36 and Northern Ireland secretary Peter Hain on 23.
The figures, published on the party website, suggest that Benn will benefit from grassroots support in the final ballot, despite initially struggling to gather the 45 MP nominations needed to reach the vote.
Ladbrokes spokesman Robin Hutchison said: "Cruddas has now overtaken Harman in the betting and is definitely one to keep an eye on.
"Benn is certainly still the front runner as far as we're concerned but the old adage about the tortoise and the hare applies as much to betting as it does to other walks of life."
Meanwhile, Gordon Brown - who has already been confirmed as Tony Blair's successor - garnered 407 nominations from local Labour groups, nearly two thirds of the 633 possible.
Labour general secretary Peter Watt said the level of support was "unprecedented" in the party's leadership contests.
"Not only are hundreds of members attending each of our hustings but across the country local activists in 407 constituencies have attended selection meetings and have chosen to nominate Gordon Brown," he said.
"The message coming out of all those meetings is clear: Labour Party members have united behind Gordon Brown as the man to lead our party and our country."
Under Labour rules a third of the votes each are designated for party members, affiliated trade union members and an electoral college of MPs and MEPs. The results will be declared on June 24.
