A bus company plans to sue families of child arsonists who torched a bus in Brighton at the weekend.

The cost of repairs to the wrecked double-decker, originally thought to be £10,000, have soared to £40,000.

Roger French, managing director of the Brighton and Hove Bus and Coach Company, said: "It will be several weeks before the bus is back in action.

"We have no insurance for the loss and we will try to win some back from the Criminal Compensation Board.

"I'm not holding out much hope of that succeeding so we may well take action in the civil courts against the parents and families of the youngsters responsible."

Four children have been arrested. One was freed on bail on Monday evening. Three others, all boys between 12 and 15, were further questioned and were also released on bail until the new year pending further inquiries.

A force spokeswoman said: "We are confident we will be bringing charges."

Passengers fled to safety as flames tore through the number 7 bus in North Street on Saturday.

A group of young teenage girls and boys at the rear of the top deck were filmed by CCTV at the scene of the fire.

The top deck of the bus was wrecked and police and East Sussex Fire and Rescue immediately launched an investigation.

Sue Heard, Brighton and Hove Police spokeswoman, said: "This was a very serious incident and it is extremely fortunate no one was injured.

"As you would expect on a Saturday just before Christmas, the bus was very busy with shoppers.

"We have a number of witnesses who saw a group of youths playing with lighters moments before the fire took hold."

Anyone with information should contact Brighton CID on 0845 6070 999.