07:47 PM EDT, 06/04/2026 (MT Newswires) -- Greater Manchester Mayor Andy Burnham has publicly confirmed for the first time his intention to challenge British Prime Minister Sir Keir Starmer for leadership of the Labour Party, Bloomberg reported Thursday.

Burnham made the declaration on BBC's Question Time, saying he would seek to represent his party at the highest level if elected to parliament in the Makerfield by-election on June 18, the report said.

Starmer's spokesperson pushed back, saying the prime minister would not walk away from his mandate, the report added.

A poll by Survation gave Burnham a 10-point lead over his nearest rival in the constituency, Bloomberg noted.