British actress Sadie Frost has described how she was left in a Berlin police cell for eight hours without food or water.

The London-based star, currently starring in Rancid Aluminium, has lodged an official complaint saying she was arrested, manhandled and locked up by officers.

German authorities have promised to investigate.

A spokesman for the 33-year-old actress said: "Sadie is very shaken by the whole affair, and she feels this was a violation of her.

"It's nothing personal against Germans or Germany and she will be going back there again, but next time she will make sure she has her passport and mobile phone on her the whole time."

Frost, whose earlier film credits include Bram Stoker's Dracula, was on her way back from a concert when the incident happened last Wednesday.

She raised the alarm after becoming stuck in a lift in the apartment block where her husband, actor Jude Law, was staying while filming in the city.

Police and fire crews arrived to free her, then demanded to see her passport and ID papers.

But when she told them she had left the documents in her husband's flat, she says they refused to believe her and arrested her instead. Frost was later released without charge.

A spokeswoman for the German Embassy in London responded to the claims by saying: "The police said Miss Frost was in a cell for four hours, not eight, and they put her in custody because she could not tell them who she was or where she was staying.

"She didn't have any ID on her, so they couldn't see who she was."

Miss Frost was checked over by a doctor and was found to have nothing wrong with her, although she had had "a bit to drink", she added.

Frost's spokesman later added that she was examined by a private doctor after the event who took photographs of her bruising.

He also said that claims that she was drunk were "incorrect".

The matter has also been referred to the Mayor of Berlin by the British Consulate.