A Rail firm is investing more than £100 million on new high speed trains between Sussex and London.

The 100mph trains have been ordered by the county's main rail operator Connex SouthCentral and will be introduced next year.

The trains will be able to shave about four minutes off the fastest times from London to Brighton, which means travellers will be able to complete the journey in 45 minutes.

The new trains will also operate on routes from Victoria to Eastbourne and from the capital towards Hove and Chichester.

By 2002, Connex aims to have replaced all Sixties slam door trains including those on the East and West Coastway routes.

It has ordered 120 Class 375 air-conditioned electric trains. One was put on show at Brighton Station last night.

The trains have more than 240 seats and carry about 20 per cent more people than existing ones.

Buying the trains is not dependent on Connex winning a new franchise for the South Central area. Connex is bidding against Thameslink for the franchise, which will be decided at the end of next month.

If Connex loses the franchise, the trains would be transferred to its South-Eastern division.

Some seats in the new carriages are airline style and others are grouped around tables. Features include disabled access and closed-circuit TV.

Connex chief executive Antoine Hurel said: "We know our customers want slam door coaches replaced as quickly as possible.

"These new trains show our determination to improve our quality of service for our customers."

He said Connex was also investing an additional £500,000 to improve cleaning on board trains this year.

Railtrack and manufacturers Adtranz have to carry out full safety tests before they can come into service.

Most passengers who were given a sneak preview of the trains by Connex appeared impressed.

Eleven-year-old Nathan Green, of Poulters Lane, Worthing, said: "They are really good trains - nice and comfortable."

Brighton and Hove Green councillor Peter West said: "They look comfortable and are a good improvement." But he was disappointed at the space left for bikes which will also not be carried in peak hours.

Retired commuter Henry Law, of Queen's Gardens, Brighton, said: "This is a thoroughly poor piece of design."

He said there would be problems if the air conditioning failed and questions needed to be asked about whether the trains would crumple in crashes.

Brighton Line Commuters spokeswoman Shelley Atlas said: "Replacing the slam doors is the biggest priority because they are so dangerous."