Police are hunting young arsonists who set fire to a train in West Sussex last night.

Passengers were evacuated from the Connex South Central Train at Lancing after smoke was seen pouring from a first-class carriage.

The alarm was raised as the four-coach train left Lancing station just after 7pm.

The driver of a train passing in the other direction noticed smoke rising from the back of the 17.53 Bognor-Seaford service and contacted signalmen.

The train pulled back into the station and up to 15 passengers were evacuated.

Fire crews from Lancing put out a blazing seat which left the carriage smokelogged.

No one was in the carriage at the time and there were no injuries.

British Transport Police are treating the fire as suspicious and want to trace two 12-year-old boys who were seen going into the carriage at Worthing and getting off at Lancing.

Connex spokesman Dave Ewart said: "Once the passengers were off the train was moved into sidings so services were not badly disrupted.

"This is a mindless act of vandalism that could have caused serious injury and damage."

Inspector Mick Morriss, of British Transport Police, said: "If the fire had not been spotted it could have spread right through the carriage and turned into a major incident. It is vital we find the people responsible."

Anyone with information should contact police on 0800 405040.