Police will no longer be stationed outside the Ecuadorean embassy in London where Wikileaks founder Julian Assange has sought refuge since 2012.
Met Police officers had been there since Mr Assange sought asylum to avoid extradition to Sweden over a rape allegation, which he denies.
The Met said it had cost £12.6m and was "no longer proportionate" - but it would still try to arrest him.
Wikileaks said the decision did not change Mr Assange's situation.
'Overt and covert'
Scotland Yard said that "resources are finite" and there were "so many different criminal, and other, threats to the city".
"The Metropolitan Police Service has to balance the interests of justice in this case with the ongoing risks to the safety of Londoners and all those we protect, investigating crime and arresting offenders wanted for serious offences, in deciding what a proportionate response is," it said.
However the force also said it would be deploying "a number of overt and covert tactics to arrest him".
Wikileaks spokesman Kristinn Hrafnsson said he had spoken to Mr Assange about the Met decision, and he agreed it did not change his situation.
"They will still arrest Julian if he steps outside the embassy so there is no real change to the situation, other than the removal of uniformed police officers," he said.
The Australian sought asylum to avoid extradition to Sweden, because he feared he would then be sent to the US and put on trial for releasing secret US documents.
The UK has paid for policing around the embassy in Knightsbridge, central London, for the past three years.
The Met provided a breakdown of the round-the-clock policing costs, which it estimated to be £12.6m - £7.1m in normal pay, £3.4m in overtime and £2.1m indirect costs.
Mr Assange was granted political asylum by Ecuador in 2012, under the 1951 Refugee Convention.
Swedish officials said recently they were optimistic about reaching an agreement with Ecuador which could pave the way for the questioning of Mr Assange in London on outstanding accusations against him.
Last month, prosecutors dropped cases of alleged sexual misconduct against the 44-year-old but say they want to question him about an accusation of rape, made after his visit to the country five years ago.
Assange assault claims: Key dates:
- August 2010 - Swedish Prosecutor's Office issues arrest warrant for Mr Assange over sex assault allegations, which he denies
- May 2012 - UK's Supreme Court rules he should be extradited to Sweden to face questioning
- June 2012 - Mr Assange enters the Ecuadorean embassy in London
- August 2012 - Ecuador grants asylum to Mr Assange, saying there are fears his human rights might be violated if he is extradited
- August 2015 - Swedish prosecutors drop their investigation into two allegations - one of sexual molestation and one of unlawful coercion because they have run out of time to question him. He still faces an accusation of rape and continues to deny the allegations
Mr Assange has previously said he would welcome being questioned at the embassy.
A Foreign Office spokesman said the Ecuadorean ambassador had been summoned by the head of the UK's diplomatic service "to register once again our deep frustration at the protracted delay.
"The UK has been absolutely clear since June 2012 that we have a legal obligation to extradite Assange to Sweden. That obligation remains today."