New high-speed railway lines could see 200mph trains linking Oxford with London in about 30 minutes, after Network Rail said today it was looking at ways of increasing capacity to meet rising demand.

A feasibility study into brand new lines, suitable for trains like the French TGV and German ICE, will include two routes between the capital and Oxfordshire.

The rail infrastructure company is to study five key routes running north and west of London, including the Great Western Main Line to Didcot, Oxford and the West of England, and the Chiltern Line, linking London with the West Midlands via Haddenham & Thame, Bicester and Banbury.

The review will also look at the East Coast, West Coast and Midland Main Line routes, as Network Rail looks into ways to cope with projected future growth after a 40 per cent rise in passenger numbers over the past decade.

Last November, the final section of the High Speed One line, between London St Pancras and Ebbsfleet, in Kent, was opened, which allows Eurostar trains to France and Belgium to run at up to 186mph to the Channel Tunnel.

A Network Rail spokesman said: "Dedicated new lines would help free up a lot of capacity on the existing network, providing space for a lot more services.

"Potentially, high-speed lines are a solution we are looking at but they would be a political decision, with a large capital cost attached to it."