Passenger groups have given a cautious welcome to the biggest shake-up of rail fares in 40 years.

The vast array of ticket choices currently offered is to be scrapped and replaced by just three single and return tickets: Advance; Anytime; and Off-peak.

The aim of the changes by the Association of Train Operating Companies (Atoc) is to make it easier to buy the best-value ticket for journeys.

The new structure will apply across all networks and Atoc claims that the vast majority of rail users will benefit from the changes. It said a "tiny, tiny, tiny" proportion would be worse off.

But Atoc has been criticised for using the change to scrap refunds for tickets and also for doubling the fee for changing journey times for return tickets bought in advance on many routes from £10 to £20.

The pricing structure has remained largely unchanged since the 1960s and Atoc said the change had been a "long- time coming".

The move, while welcomed in principle, was criticised by some passenger groups.

The Campaign for Better Transport called on the UK government to reduce the cost of rail fares, especially for last-minute journeys.

The campaign's executive director Stephen Joseph said: "Advance tickets are sometimes cheap, but people can't always plan their journeys weeks beforehand. The government must make train travel the cheap and easy option if we're going to reduce carbon emissions from transport."

Anthony Smith, chief executive of rail customer watchdog Passenger Focus, said: "Simplifying the range of fares is a big step in the right direction.

"Anything that hacks away at the current fares jungle will help."

Gerry Doherty, leader of the TSSA rail union, said: "This will hit the passengers who can least afford it - the young and the elderly who can only afford to travel by paying in advance.

"These changes are meant to make rail travel easier. They should not be used as an excuse to increase profits by scrapping refunds."