First Great Western chief executive Andrew Haines has promised improvements are on track.

Mr Haines said he expected infrastructure improvements, such as converting lines used for freight into passenger routes, an additional platform at Oxford and the doubling of sections of the Cotswold line would all ease congestion, which he blamed for most of FGW delays.

Network Rail is responsible for the railway's infrastructure.

Mr Haines, of East Hanney, said about 70 per cent of delays in the Thames Valley were the fault of Network Rail, and FGW and Network Rail were working together, "identifying changes needed".

Network Rail said only 48 per cent of delays were its responsibility.

Mr Haines added: "Historically, there were 200 trains running a day on the First Great Western network. Now there are 1,400.

"Our biggest problem now is dealing with growth.

"Fourteen years ago, the industry was dealing with decline."

Ox Rail Action spokesman Zahra Akkerhuys said: "Mr Haines has recognised that he needs to do more than just tinker at the edges and that radical action needs to be taken if the service his company delivers is to be improved."