Recent Labour Party turmoil after weak local election results has intensified speculation over Keir Starmer's future, positioning Greater Manchester Mayor Andy Burnham as the leading contender to become the next prime minister. Burnham's strong polling among party members, combined with his push to return to Parliament via a Makerfield by-election approved by the National Executive Committee, has driven trader consensus toward him at 56.5% implied probability. Wes Streeting's cabinet resignation and Angela Rayner's cleared path have fueled parallel bids but at lower levels around 9.5% each, reflecting Burnham's broader appeal and devolution record. With a potential leadership contest looming before summer recess or the autumn conference, outcomes remain fluid pending the by-election and any formal challenge.