The government is to grant Ken Livingstone control of a key London overground rail service.

The mayor will take over the running of Silverlink Metro services in November 2007, ministers announced on Tuesday.

The move will give the mayor's Transport for London agency time to upgrade services and stations in time for the 2012 Olympics.

Transport secretary Alistair Darling said: "Part of the Silverlink Metro service includes the North London Line, which is a crucial link to the 2012 Olympics.

"The government, TfL and London 2012 are developing plans to greatly enhance the capacity of the line both in preparation for the Games and to leave a lasting legacy."

Ministers also want greater co-ordination of transport policy in the region, with several overground services sharing stations with the underground system which already falls under the mayor's control.

Silverlink's services, while nominally national, fall almost entirely within the Greater London Authority's boundaries.

Following recent criticism of passenger safety on the rail system, Livingstone also promised to make protecting the public his "first priority".

"Today's announcement means that, from 2007, Transport for London can begin to revitalise London's overground rail services just as it has done with buses and is doing on the Tube," he said.

"In addition to improved services, my first priority will be station safety and security, which means putting staff back into the stations where the public want to see them.

"Stations that are currently often understaffed or empty altogether will be staffed adequately, offering passengers a more visible and reassuring presence.

"Stations and trains will be improved with additional security enhancements including CCTV at stations and on trains."

The announcement came on the same day Livingstone submitted his response to a government consultation on devolving more powers to his office.

The mayor appealed for the right to set skills, waste and planning policy for Londoners.

"Future success depends on providing the elected office of mayor with the right set of powers to tackle the problems we face - skills provision according to the capital’s needs in the run-up to the Olympics, a citywide waste authority to oversee the recycling and management of the city’s waste, and planning and housing powers to provide Londoners with the affordable homes they so badly need," he said.