Labour leadership hopeful Yvette Cooper has gained ground in the contest, after she overtook Andy Burnham as second favourite with one bookmaker and closed the gap with a number of others.
Ladbrokes shortened its odds on Cooper to become the next leader, from 10/1 to 5/1, in second place to frontrunner Jeremy Corbyn at 2/7, with Burnham has fallen behind at 6/1. Liz Kendall, the final candidate, is out at the back with odds of 100/1.
Meanwhile, a host of other bookmakers have shortened their odds on a win by Cooper, offering between 7/1 to 8/1, while Burnham is offered at between 5/1 and 7/1.
Matthew Shaddick, head of political betting at Ladbrokes, said there was a build up in optimism around the Cooper campaign in the last few days.
"The Burnham campaign has been terrible in the last few days, while Cooper's has been markedly better with positive factors such as her intervention on refugees," Shaddick added. "But, it's probably too late for her to catch Corbyn, especially as many of the votes in the contest will already have been cast."
Betway also slashed odds to 3/1 on Cooper, down from 10/1 earlier today, after a flurry of bets. Betway's Alan Alger said:
Yvette Cooper's recent comments on the refugee crisis look to have earned her plenty of support and we think her bid for Labour leadership is far stronger as a result.
A number of polls still have Corbyn winning by a large margin, with the most recent YouGov poll showing the veteran MP for Islington North will come out in front in the first round with 43 per cent of the vote. Burnham was in second place with 26 per cent of the vote, while Cooper came in third with 20 per cent, and Kendall claimed just 11 per cent.
The change in odds came ahead of the final hustings event tonight, where the four candidates will answer questions from the public.
Ladbrokes have also altered their odds of who will be Labour leader at the next General Election. While Corbyn still leads at 6/4, he is followed by Dan Jarvis and David Miliband at 6/1 and 8/1 respectively, who lead Burnham and Cooper, both at 10/1.