Before 11 December the cost of the journey was �5 per day, but it now costs �7 for a return trip.

One passenger said some of her colleagues who used the route have now resorted to driving again.

First's Area operations director Russell Barrington-Crow said there had been an "oversight" and that the company would consider a reduction.

"This particular fare increase is an anomaly. Clearly it doesn't reflect fare increases across the board.

"We obviously have a vast number of fares right across the area. "

Mr Barrington-Crow admitted the fare "does seem to have gone up more than the others".