A double decker bus smash was caused when a driver took a wrong turn, bosses have revealed.

The bus which smashed into a railway bridge in South Norwood should not have been on the road.

Two passengers were injured when a 197 route bus slammed into the railway bridge over Portland Road.

The structure has been struck 42 times over the past 12 years and railway engineers have repeatedly warned the 12ft height is too short for high vehicles like double deckers.

The crash happened at about 11.30pm on Friday, peeling back about a third of the roof on the top deck, injuring two passengers and leaving another 15 badly shaken.

Two fast response cars and an ambulance raced to the accident scene. Two people were taken to King's College Hospital with minor injuries, while another two were taken to a nearby address suffering from shock.

A Network Rail spokesman told the Croydon Guardian: "We went out to the incident a couple of hours after it happened so delays were kept to a minimum for passengers.

"The bridge is not high enough for double decker buses to pass through, it should not have been going underneath it.

"We would advise drivers to pay more attention to bridge heights and vehicle heights to avoid incidents like this. It is unsafe, it costs us time and money and can be avoided."

Jay DeVlieger, manager of the Port Manor pub and restaurant, was outside his business in Portland Road when the bus smashed into the bridge.

He said: "I heard a loud noise and turned around to see the bus wedged underneath the bridge. I ran over to the driver to see if he was OK and then helped the elderly passengers by grabbing some chairs for them to sit on. It was a mess."

Local restaurant worker, Kerry Edwards, 32, said: "I went outside and it was carnage. There was glass and bits of debris everywhere."

Dave Jones, commercial support manager for Arriva London, said the driver should have turned right into Manor Road instead of trying to go underneath the railway bridge.