Train carriages could be diverted from Brighton to cope with passenger overcrowding in the east of the county.

Norman Baker, Lewes's Liberal Democrat MP, made the suggestion when he met with Southern trains managing director Chris Burchell recently to discuss overcrowding.

The MP, who is the Lib Dem’s transport spokesman, said he welcomed the fact that Southern were treating overcrowding on trains as a serious problem.

He said: "The new timetable introduced last year produced a number of unwelcome consequences for passengers travelling to Plumpton, Lewes, Polegate and beyond, not least the fact that the number of evening rush-hour carriages actually reduced.

"I have been pressing Southern very hard to deal with this matter and hope it will not be long before trains are lengthened by four carriages each.

"The meeting on Monday also revealed something else we had all suspected, namely that trains to Brighton are more lightly loaded than trains to Lewes and Eastbourne. Last year the Department for Transport required Southern to run three Gatwick trains through to Brighton in the evening peak. I have now formally asked Transport Secretary Andrew Adonis, in a letter to him this week, to redirect one of those trains off the Brighton line and to Lewes and Eastbourne instead.”

Sharon Hedges, from watchdog Passenger Focus, said: "We've urged Southern to look closely at passenger needs and adapt services to better fit demand. A fundamental review of all services from Sussex Coast to London is well overdue and we're calling for all parties to take steps to introduce a better timetable as soon as possible."

A spokesman for Southern admitted that several services needed extra carriages but that the firm did not have the rolling stock.

He said: “In May 2010, additional rolling stock will be introduced which will free up some carriages for strengthening services elsewhere on the Southern network, but we will not be able to strengthen all trains where this requirement exists.

“In the meantime, we will continue to strive to match our current resources against demand as closely as we can.”

He added: “We have taken all Mr Baker’s suggestions on board for consideration in light of potential effects these may also have on the rest of the Southern network.”