The go-ahead for improvements to the Cotswold Line rail route between Oxford and Worcester was tonight welcomed by rail campaigners.

The Office of Rail Regulation gave its ruling yesterday on how much money Network Rail will have to spend on the rail system between 2009 and 2014.

The document gave final confirmation Network Rail would be allocated funds to reinstate about 20 miles of double track on the line, reversing a 1970s cost-cutting measure.

Derek Potter, the chairman of the Cotswold Line Promotion Group, which represents passengers on the route, said he hoped the project would improve the "patchy" service from train operator First Great Western. He said: “It's good news. What we should get is reliability. If you turn up for a train at 7.05am it should be there at 7.05am, not 7.10am or 7.15am, or not at all.”

Under the Network Rail proposals, about five miles of track from just east of Charlbury to Ascott-under-Wychwood and another 15 miles between Moreton-in-Marsh, in Gloucestershire, and Evesham, in Worcestershire, will get an extra set of rails.

The 11-mile section between Ascott-under-Wychwood and Moreton-in-Marsh already has double track.

The section between Wolvercot junction, north of Oxford, and Charlbury will remain single track for the time being.

A First Great Western spokesman said the company believed the work would improve reliability of its services in Oxfordshire.

Network Rail’s strategic business plan, submitted to the ORR earlier this year, put the cost of the improvements at £51m, with work scheduled to begin next year and be completed by late in 2010.

In July, the ORR indicated it would back the plan but said it believed the work could be completed for £48m.

However, consultants advising the ORR said costs could hit £105m, while Network Rail told the Oxford Mail in April that revised estimates put the cost at between £67m and £95m.