A Boris Johnson aide dined out with the leader of Kensington and Chelsea on expenses before resigning for using his City Hall credit card inappropriately.

Mayoral deputy Ian Clement handed in his notice on Monday after spending more than £2,000 on flight upgrades, dinner with fellow Conservatives and groceries, on a corporate card. His actions broke rules which stipulate such cards should only be used in 'exceptional circumstance' and have 'no private use'.

Among his expense claims were at least four meetings with council leader Councillor Cockell - ranging from an £8.50 coffee in a Birmingham hotel, to a whopping £704.44 dinner at the Gotham Bar and Grill in Manhattan. Mr Clement also claimed for upgrades on two long-haul trips to China and groceries from Tesco.

Last Wednesday, at Mayoral Question Time in City Hall, Mr Johnson said he was 'more than a little miffed' when he discovered the use of the card. "I think it was wrong and will not happen again. Ian has made an apology," he said.

He stressed that Mr Clement - who the mayor said earns at least £124,000 a year - had made no personal gain from his expenses. But on Monday, after a weekend of thought and revelations in the Evening Standard that some guests were not present at meals, Mr Clement - who was on some occasions thought to be dining with his lover - stood down.

In a letter to the mayor, he wrote: "It has been a pleasure to work for you and I am sorry that I have let you down."