Ministers announced a dramatic u-turn over rail policy today, scrapping the Strategic Rail Authority just four years after it was set up.

Transport Secretary Alistair Darling told the Commons the majority of the SRA's functions would be transferred to the Secretary of State.

Unveiling a White Paper on the railways, he said overall responsibility for the network would pass to Network Rail, which would have responsibility for ensuring that it delivers a reliable service.

Under the streamlining plans there will also be increased powers for the Scottish Executive, the Welsh Assembly and the London Mayor to fund and plan rail services.

Mr Darling said the changes would ''put the railways on a stable long-term footing and tackle the remaining flaws left from privatisation''. But shadow transport secretary Tim Yeo said that ''shifting responsibilities around Whitehall, replacing one set of bureaucrats with another'' would not make the trains more reliable.

Mr Darling said his plans would provide a ''single point of accountability for performance; allow closer working between track and train and provide for greater local and devolved decision-making.

''Together these proposals will make sure that Britain's railways are run in the public interest - for the benefit of its passengers and freight customers.''

He said the Government will take charge of setting the overall strategy for the railways, with ministers setting performance levels and responsible for investment.

Overall responsibility for the network will pass to Network Rail.''Too often under the present system companies have been able to pass the buck for poor performance.

''So in future, Network Rail will be responsible for ensuring that the nework delivers a reliable service through an agreement with the Government.''

The new structure, he said, would provide for closer working between Network Rail and the train companies - replacing the current ''sometimes confrontational relationship''.

Mr Darling said the number of franchises would be reduced and there would be greater clarity on the responsibilities of track and train companies.

In Scotland, the Scottish Executive will be given responsibility for planning, specifying and managing services under the existing franchise. In Wales, the Assembly will be given additional responsibilities to specify services and fares for local train services and be responsible for their funding.

In London, the Mayor will be given responsibility for rail services within the GLA boundary, and possibly beyond. Community railway lines will be put on a ''better financial footing'' and Passenger Transport Executives will be able to buy additional services. Responsibility for railway safety will be transferred to the Office of Rail Regulation.

Mr Darling said: ''At a time when the railways are carrying more people than they have done in the last 40 years, it is essential we have a more customer-focused and passenger-friendly railway.

''I am streamlining the structure of the railway in order to improve standards and make rail more attractive for passengers.''