The WikiLeaks founder has been holed up in the embassy since 2012 to avoid extradition to Sweden over an allegation of rape, which he denies.
The 46-year-old fears extradition to Sweden would lead to extradition to the US, where he is wanted over leaked documents.
Swedish prosecutors have since decided to drop the rape investigation into Mr Assange, but British police have said he would be arrested for breaching bail conditions should he leave the building.
A spokesman for Britain’s Crown Prosecution Service said Mr Assange was ”seeking to have the warrant of arrest discontinued because the Swedes have confirmed that the extradition warrant is no longer live”.
“He is seeking that therefore the warrant of arrest should be taken out as well.” Asked if a successful ruling could enable Mr Assange to walk free, the spokesman replied: “hypothetically yes, that would be our interpretation”.
More about: Assange