The mayor prefers to travel on his bicycle
London Mayor Boris Johnson's expenses have come into focus after it emerged that his taxi bill submitted to City Hall was almost half the actual cost.
In the expenses reported to the Greater London Authority's (GLA) audit panel Mr Johnson claimed £1,900 for taxi rides between April 2008 and January 2009.
But the full detailed account of his taxi bill seen by BBC London puts the figure at £4,280 for the same period.
The mayor's office cited "slowness in invoices being presented" as the cause.
The audit panel has said it is "concerned" about the delay.
Mr Johnson's expenses were highlighted on the same day that his former deputy for external affairs, Ian Clement, was reported to the Metropolitan Police over claims of misusing a corporate credit card.
Mr Clement, who stepped down on Monday, admitted spending £2,300 on personal items with his City Hall card.
Taxi rides 'approved'
Regarding Mr Johnson's taxi expenses, the detailed account shows he ran up a bill of £100 on each of 10 taxi journeys within London.
On two occasions the bill went over £200 for events attended by the mayor in Bexleyheath, south-east London, and in Edmonton, north London. It has been suggested that the taxi may have been kept waiting.
The accounts also show the mayor taking taxis from his home in Islington, north London, to the City Hall and on other occasions from work to home.
The GLA's staff guidelines state that a taxi can be kept waiting for a maximum of 20 minutes, and that a ride home or vice-versa should happen only in exceptional circumstances.
Mr Johnson said: "As far as I know some of these taxi bills referred to are journeys that I had taken to places to do engagements with, for instance, the people's question time or whatever it happens to be.
"They have all, as far as I know, been approved in the normal way," he said.
A spokesperson for Mr Johnson said: "The mayor's preferred mode of transport is his bike which accounts for the vast majority of his personal and official journeys.
"On occasions, however, over the past 14 months taking taxis has been unavoidable. That is very much the exception and the figures show he takes fewer than three taxis a week on average.
"Most of the taxis in this bill were booked in the first few months of his administration when he attended a huge number of events often going to two and three in a row on a tight schedule.
"His use of taxis has declined steadily from the start of this year. The latest figures show only 11 taxis were booked between January and March," the spokesman said.
The Labour Party at City Hall has demanded an "explanation for the discrepancies" in the mayor's accounts.