A Tube line has reopened for the first time since the 7 July bombings.
The Hammersmith and City Line was affected by the Aldgate and Edgware Road attacks and further suspended because of planned engineering works.
London Underground (LU) added that the Piccadilly Line, closed between Hyde Park Corner and Arnos Grove, should reopen completely on Thursday.
The District Line opened last week but it is not known when the Circle Line, also shut since 7 July, will open.
There is no service at the moment between Rayners Lane and Uxbridge on the Piccadilly Line either.
London Underground said that until further notice, a special bus service would call at Arnos Grove and Finchley Central to provide a connection with the Northern Line.
A second special bus service would operate from Arnos Grove calling at Bounds Green, Wood Green, Turnpike Lane and Seven Sisters to connect with Victoria Line services.
Additional bus services are operating on route 91 between Holloway Road and Euston via Caledonian Road and King's Cross St Pancras.