The Mayor of London has finally revealed who he will back in the Labour leadership contest - and it's bad new for Jeremy Corbyn, losing out on support from the most high-profile elected politician in the party.
Sadiq Khan has publicly endorsed Owen Smith in the race to lead the party after previously nominating Corbyn for the position, but voting for Andy Burnham in last year's contest.
The mayor added insult to injury by issuing a stark warning that Labour faces "almost-certain defeat" at the next General Election without a new leader.
Khan last week kept schtum when grilled by LBC radio over who he backed in the crunch contest, however, the mayor has made some sharp criticisms of Corbyn's time at the top: just days into his new job leading the capital, he told Labour to "get into the habit of winnng".
Now the mayor has gone a step further, saying Corbyn is not the one who can lead the party to victory.
"By every available measure, if Jeremy remains as leader, Labour is extremely unlikely to win the next general election," he said, writing in the Observer.
"The hopes of the members who have joined our party would be dashed again. Jeremy has already proved that he is unable to organise an effective team, and has failed to win the trust and respect of the British people."
He continued: "Jeremy’s personal ratings are the worst of any opposition leader on record – and the Labour party is suffering badly as a result. He has lost the confidence of more than 80 per cent of Labour’s MPs in parliament – and I am afraid we simply cannot afford to go on like this."
He also attacked Corbyn's response to the result of the EU referendum and said Smith - the only contender to Corbyn - had much greater popularity among the general public, giving him a greater chance of winning an election.
The Labour leadership vote is due to take place on 24 September.