A busy commuter train was pulled back into the station after a man boarded it with a gun.

Armed police surrounded the 7.26am departure from East Grinstead when it returned to the station.

They searched the carriages and every member of public on board.

Trains were cancelled and replacement bus services ran between East Grinstead and Oxted.

A police spokesman said: "There were reports of a man with a gun getting on a train from East Grinstead to London Bridge.

"As a result we brought the train back and cleared the platform and then searched the train systematically."

A man was arrested and an imitation firearm recovered.

Chief Superintendent Nick Wilkinson, who led the operation, said no threats had been made to any members of the public.

He added: "Public safety was paramount throughout the operation. Whilst we apologise to anyone who was inconvenienced or whose journey was delayed, I am pleased that we were able to achieve a speedy and a safe resolution to the incident."

The train was returned to Southern at 8.50am, when a normal service was resumed.