A passenger group has called on Oxfordshire rail operator First Great Western to invest more money in its network after its parent company reported a sharp hike in its fortunes.

FirstGroup said its annual operating profits reached £360.1m for the year to March 31 - a rise of 39 per cent on a year earlier.

Tonight Derek Potter, chairman of the Cotswold Line Promotion Group, said: "If this company is generating clear profits, I would like to see some of that invested back for the users of the service.

"I want to see it making a profit but if that profit is being helped by higher than inflation price increases, I would like to see it being invested back into the network."

In January, passengers were hit with above-inflation fare rises across the network, despite coming bottom of the Office of Rail Regulation's performance tables in the last three months of 2007, with just 79.7 per cent of trains on time.

It received a formal rebuke from the Government for its handling of the rail franchise and was forced into a £29m programme of improvements.

Last month, 88.9 per cent of Thames Valley rush-hour trains were on time, just below its 92 per cent target - while 91.1 per cent of its long-distance expresses were punctual, beating the 90 per cent target.

FirstGroup chief executive Moir Lockhead said: "This has been a year of significant achievement for the group."