Jeremy Corbyn was absent as Sadiq Khan was sworn in as London mayor - drawing a huge cheer as he declared: "My name is Sadiq Khan, I am the Mayor of London."
Khan was this morning confirmed as the new resident of City Hall after securing the biggest electoral mandate in British history over Tory candidate Zac Goldsmith, who was accused of running a "dog whistle racism" campaign based on the Labour MP's Muslim faith.
At the signing-in ceremony at Southwark Cathedral, Khan was introduced by Doreen Lawrence, mother of Stephen Lawrence, and spoke to an audience that included former Labour leader Ed Miliband and actor Sir Ian McKellan (see pictures below).
In his address, he pledged to be a "Mayor for all Londoners".
But Corbyn, the current Labour leader, was notable by his absence.
One major attack line used by the Tories was how Khan would be "Corbyn's man in City Hall", a suggestion Khan resisted.
HuffPost UK understands Corbyn's advisers are keen for the leader to be seen basking in the glow of Labour's shining light in a dire round of elections that pushed the party back to third place in Scotland.
Corbyn is thought to have congratulated Khan at a victory party.
At the ceremony, Khan was given a huge roar when he declared: "My name is Sadiq Khan, I am the Mayor of London."
In his speech, made at the Cathedral to stress his multi-faith approach, he said: "I'm determined to lead the most transparent, engaged and accessible administration London has ever seen, and to represent every single community, and every single part of our city. A Mayor for all Londoners.
"So I wanted to do the signing-in ceremony here. In the very heart of our city, surrounded by Londoners of all backgrounds."
He added: "I'm only here today because of the opportunity and helping hand that our city gave me and my family. And my burning ambition for our city, that will guide my mayoralty, is to ensure that all Londoners get the opportunities that this city gave to me.
"My promise to you is this. I promise you I will always do everything I can in my power to make our city better. I will be a Mayor for Londoners."