The energy saving benefits of a switch to public transport are being overwhelmed by rising rail fares, according to Sustrans.

Sustrans operates to promote resource and energy saving measures in transport of all kinds.

However, it currently has concerns about the potential for rail travel to replace car journeys, due to the high price of tickets.

Policy director Peter Lipman says: "Over the last 30 years public transport fares have consistently increased - often above the rate of inflation."

Meanwhile, he adds, the cost of owning and driving a car has reduced year by year, falling in real terms by 17 per cent in the past three decades.

His comments follow reports that rail prices could rise by as much as eight per cent in the year to come.

This would represent the single largest hike in costs for rail transport since the network was privatised during the 1990s, Sustrans adds.