Train passengers have been promised a major overhaul of rail services which could almost halve overcrowding on one of the UK's busiest train lines.

The Strategic Rail Authority (SRA) has challenged operators to massively expand the number and size of trains on the Brighton line.

At the moment, peak-hour fast trains pulling into London have 30 per cent more people on board than they have seats.

The SRA decided to target the Brighton line for restructuring because performance "is below an acceptable standard".

The SRA's draft proposals for the next ten years promise to take the load off overcrowded peak-hour trains by extending Gatwick Express services.

Fast Gatwick Express trains would also travel to and from the coast.

The SRA wants all peak-hour trains north of Gatwick to comprise 12 carriages.

By abandoning the splitting and joining of trains at Haywards Heath, it also hopes to shave up to ten minutes off many journeys.

Some services would be axed under the SRA's draft plans.

The Hastings to London Victoria service would now start and end at Eastbourne, while the Watford to Brighton service would be scrapped, becoming a Watford to Clapham Junction service instead.

There would no longer always be a train waiting at Gatwick to go to London.

But the SRA is confident, after consulting passenger groups, local authorities and rail operators, that its Gatwick-centred strategy will boost services across the network.

Gatwick plays a key role in the plans, partly because of anticipated expansion at the airport and BAA's target of 40 per cent of its workers using public transport by 2008.

Under the scheme, the number of 28-minute Gatwick Express trains from Victoria each hour would go up from four to six.

Of these, two would carry on to Brighton, one to Bognor, one to Littlehampton, one to Portsmouth and one to Southampton.

The trains would run every ten minutes from Victoria and Gatwick.

Most Gatwick Express trains are presently only 40 to 50 per cent full.

The SRA predicted its expansion of carriages would mean mainline trains were 80 per cent full on leaving Gatwick for Victoria in the morning peak hours, rather than 130 per cent.

Thameslink trains arriving at London between 7.30am and 9am travel at an average 160 per cent capacity.

As well as ending the Haywards Heath split, the SRA also proposes to improve punctuality by reducing complex train moves between lines and tailoring timetables to the speed of new trains.

There would also be hourly fast services to Uckfield from London Bridge and an extra fast service between Brighton and Ashford, partly to compensate for ending the Hastings link.

SRA chairman Richard Bowker said: "This strategy marks a major step towards delivering a better railway for users of the Brighton main line."