Rail passengers have been left "bitterly disappointed" over a decision not to electrify two East Sussex lines.

Commuters have long campaigned for electrification on routes between Uckfield and Hurst Green and Hastings and Ashford.

At present, the routes are serviced by diesel trains which members of the watchdog Rail Passengers Committee (RPC) claim are slow and uncomfortable.

Wendy Toms, chairman of the southern branch of the RPC, said: "We are bitterly disappointed.

"It seems to us remarkable that as almost two years ago the Strategic Rail Authority (SRA) announced these two long overdue electrification schemes as high priorities.

"It included them in its strategic plan only six months ago but it is now claiming that most of the benefits that passengers want can be achieved through the use of new diesel trains on these routes.

"If the SRA can demonstrate to us how this can be done, my committee would be prepared to reconsider its present commitment to electrification and double-tracking, but so far the case has certainly not been made."

A spokeswoman for the SRA said a preliminary assessment had found there was not a case for electrification along the routes.

She said: "Circumstances may change and we intend to do a feasibility study for electrification on both the routes in the future."

The spokeswoman said in the meantime there were plans to replace the diesel trains with new stock by the end of 2004.

Ms Toms said the South East suffered from a transport system that was failing to deliver to commuters but gave a cautious welcome to SRA's plans to carry out a feasibility study and provide new rolling stock.

She said: "What passengers want is newer, cleaner, more comfortable trains so they don't have to change from their diesel trains at Oxted and at Ashford International on to electric trains. They also want faster, more frequent services.

"New diesel trains will certainly mean that passengers travel in greater comfort but it is hard to see how these trains will bring any other benefits."