Sadiq Khan is being accused of "selling off the family silver" to help plug a hole in the finances of the capital's transport system, as figures showed that Transport for London shed more half a billion pounds worth of land and assets last year.

An analysis of official reports shows that TfL sold property and other assets totalling £650 million in the last financial year, with the body forecasting another £182 million worth of sales this year.

The disclosure comes after TfL, which is chaired by Mr Khan, reported a budget deficit of almost £1 billion last year, prompting economists to warn that the transport authority was operating on a "knife edge".

As a result of its ownership of the land around London Underground stations, the transport authority is one of the capital's largest landowners, with 5,700 acres across the city .

Rory Stewart, the former Conserverative cabinet minister who is standing as an independent candidate in the London mayoral elections, claimed that Mr Khan was "selling off the family silver" for a short term "cash rush".

Mr Stewart said: "Because he's not managing the finances of the Tube properly, what he has been quietly doing is selling off our land, our family silver, in order to cover the running costs of the Tube.

"He has taken it as a short term cash rush. But what he's doing is depriving our children and grandchildren of the land on which we could be building affordable housing."