Andy Burnham has secured nominations from 322 of Labour's 403 MPs in the leadership contest.
One more nomination would make Burnham the only candidate eligible to replace Keir Starmer.
Burnham is expected to be confirmed as Labour leader next week and officially named prime minister on 20 July.
Andy Burnham is on course to become Britain's next prime minister after winning the backing of an overwhelming majority of Labour MPs, leaving him just one nomination short of becoming the party's sole leadership candidate to replace Keir Starmer.
According to Reuters, Burnham's early support has all but settled the Labour leadership contest. If he secures a 323rd nomination, no other candidate will be able to reach the 81 nominations required to enter the race, paving the way for him to be confirmed as Labour leader before taking office as prime minister later this month.
Burnham said he had received nominations from 322 of Labour's 403 members of parliament on the first day of nominations on Thursday.
"It's all starting to feel very real," Burnham said in a short video clip announcing he had nominated himself.
Reuters reported that nominations for the Labour leadership close next Thursday. Burnham is expected to be formally confirmed as Labour leader next Friday before being officially named prime minister on 20 July.
Some Labour MPs who were unable to vote on Thursday have said they will back Burnham when they return to parliament on Monday, according to Reuters.
Burnham's path to the leadership was effectively secured on Wednesday night after Al Carns, the former junior defence minister, said he would not stand against him.
Starmer announced his resignation last month after Labour's poor performance in local elections in May prompted growing calls from lawmakers for a change of leadership and direction, Reuters reported.
(With inputs from Reuters)
