A woman train conductor has been arrested for allegedly being drunk while working on a commuter service, British Transport Police said.

The alleged incident happened on the 17.50 Connex South Central service from London Bridge to East Grinstead last Friday, a police spokesman said.

The woman, who was not named by police, was later released on police bail to return for further questioning in June.

BTP Inspector Gary Young said: "British Transport Police are investigating an allegation that a conductor employed by Connex was unfit through drink while working on the 17.50 service from London Bridge to East Grinstead on Friday, April 20.

"One member of staff was arrested in connection with this allegation and has been bailed to appear at Peckham police station in June, pending further police inquiries."

A Connex South Central spokesman said an internal investigation was being held.

He could not confirm if the conductor had been suspended but said delays to passengers were kept to a minimum.