The mayor wants to bring commuter trains under TfL's control

The mayor's Transport for London (TfL) is responsible for Tube, buses and trams but now Mr Livingstone wants to bring trains under his control as well.

A London regional rail authority would provide a more integrated service and raise standards, he said on Tuesday.

But the Strategic Rail Authority (SRA) is sceptical and there are concerns about fragmenting the rail network.

Twelve train operators carry passengers in and out of London - that could be cut to three and franchises could be shortened to five years under the plans.

Mr Livingstone says he wants a more simple fare structure - it currently costs �1.70 to go from zones one to three on the Tube, but up to �3.70 on a train.

And he says a London rail authority would bring better services, shorter queues for the ticket office and better stations and security.

"It would mean we can start to bring major transport improvements to large parts of London not covered by the Tube network," he said.

Mr Livingstone has made transport a priority

"If we start with a shadow form of running the London rail authority, changes can start to be made relatively fast."

He said the government had recognised the plans were practical.

Transport Secretary Alistair Darling told The BBC's World at One programme they needed to look at whether bodies like TfL could take responsibility for local services.

But he said: "What you need to watch though, in all of this, is that you don't end up Balkanising the railways. There is one railway. It needs to be run in a way that is consistent.

"We need to...make sure there is a simplified, streamlined organisation that can run the railways properly and control costs.

"Now that means you do need to have a single guiding mind. It does not mean you have got to have the same people owning the track as owning the railway trains."

Shadow Transport Secretary Theresa May said she had doubts TfL had the "kind of top level experience" required to do the job .

And she questioned whether tax payers would end up compensating the companies currently operating franchises.