When Boris himself arrived at the party at Burberry's global head office in Horseferry Road, he was greeted with a kiss by BBC London anchor Riz Lateef, who features on the list of London's 1,000 most influential people for the second year.
Ms Lateef, who has joined the pool of newsreaders for the BBC's main weekend bulletins, said: "I think I was the first person he recognised."
She added: "I'm normally stuck in the studio so to feel the buzz of London first-hand is great."
Mr Johnson denied David Cameron's charge that he had "put his size 10 feet in it" at the Tory party conference by demanding a referendum on Europe. "I take size 10-and-a-half," he said.
Mr Johnson also jokingly offered Mr Livingstone the post of "deputy mayor for reconciliation". The former mayor said he was ready to resume his old role.
"You have just missed it," he told the Standard. "Boris has promised to resign immediately."
The Mayor, who was crowned the most influential Londoner, said: "I'm proud to be the man rated the most influential person in the most influential city on Earth."
Other guests included Business Secretary Lord Mandelson, Topshop boss Sir Philip Green, Olympic 400m champion Christine Ohuruogu, BBC boss Alan Yentob, Transport Secretary Lord Adonis, former Tory vice-chairman Jeffrey Archer, ex-Rolling Stone wife Jo Wood and Duran Duran keyboard player Nick Rhodes.
Met police commissioner Sir Paul Stephenson mingled with designer Anya Hindmarch, O2 arena chief executive David Campbell, lastminute.com co-founder Brent Hoberman, Gordon Brown's official spokesman Simon Lewis and singer and former Neighbours actress Holly Valance.
Ms Ohuruogu, who plans to defend her Commonwealth title in Delhi next year, said: "It's great to see such an eclectic mix of different communities. "It makes you realise how diverse London is and what Londoners are doing internationally. I want to take photos but I can't."
