FIRST Great Western is increasing some of its off peak fares by more than four per cent.

It says the price rises, which will be implemented on June 2, will help pay for investment in its services.

Fares set to rise include supersaver, cheap day return, superadvance and advance and have been held at the same price since May 2000.

The Swindon-based company says it will continue to freeze its cheapest fares, Apex and First Apex.

Elaine Holt, First Great Western's director and general manager of commercial services, said: "We have invested heavily in all areas to benefit our customers including the introduction of our new Adelante fleet of trains.

"Our existing trains have been refurbished, we have more staff and improved customer service and communication."

The company has been embroiled in controversy because of its high fares and poor performance.

Its route between Swindon, London Paddington and Bristol has been dubbed the most expensive in Europe.

It has been dogged by problems with its services, leading it to be nominated in a recent BBC programme looking at Britain's worst rail operators. But reliability has improve in recent months and the company insists it is continuing to increase efficiency and comfort for its passengers.

John Main, assistant secretary of the Rail Passenger's Committees in the West of England, said: "We would tell First Great Western: 'OK, you have increased rail fares now tell us how you are using our money to improve services'.

"The company has made investments but that has been and gone. Now we need to see services improve further."

Ms Holt said: "We are now working closely with the Rail Passengers' Committees to ensure further customer benefits.

"We have established a constructive relationship with it and have open channels of communication.

"We have taken on board their comments and recommendations following its investigation and will be discussing our plans for future investment with it as it starts to be introduced.

"We are not over promising and will deliver new investment in all areas."