Spend on operation to attempt arrest and extradition of Wikileaks founder is described as ridiculous by London assembly member

The cost of maintaining a round-the-clock guard outside the Ecuadorian embassy to prevent the escape of Wikileaks founder Julian Assange has risen to £3.8m, the Metropolitan police have revealed.

The amount, which covers the period between June 2012 and the end of May 2013, was disclosed in response to a letter to London assembly member Jenny Jones, who said the constant police presence outside the embassy in Knightsbridge, west London, was stretching resources, describing it as ridiculous.

The Metropolitan police commissioner, Sir Bernard Hogan-Howe, said in his reply to Jones that £0.7m of the total represented additional costs incurred as a result of increased overtime payments. He also said that the Met had not yet formally sought reimbursement from the Home Office for the costs but that they were now in early discussions concerning the matter.

Green party member Jones said: "It's ridiculous that for over a year now the Metropolitan police service have been stationed outside the Ecuadorean embassy waiting for Julian Assange to attempt an escape. At a time when the Met is making cuts how can this be a priority for the police? This situation cannot be allowed to continue indefinitely. The mayor really should be trying to find a solution to this stalemate because in the meantime the Met is spending time and resources on an expensive stakeout."

Assange walked into the embassy on 19 June last year in an attempt to avoid extradition to Sweden to face sex assault and rape accusations, which he denies. In August last year, Ecuador granted him political asylum but the police are stationed outside the building to arrest him if he leaves the building.

The foreign secretary, William Hague, and his Ecuadorean opposite number, Ricardo Patiño, met last month to discuss the ongoing diplomatic stalemate, but were unable to reach agreement.

Assange subsequently said he would not leave the embassy even if Sweden drops its extradition bid, because he fears moves are already underway by the US to prosecute him on espionage charges.