A mental health nurse forged a doctor's signature to get a prisoner medication before raping her, a court has heard.

Peter Barrowman, 35, of Stenhousemuir, Falkirk, is alleged to have targeted three prisoners at HMP Cornton Vale and supplied them with drugs.

On Wednesday, a 26-year-old witness told a jury at the High Court in Glasgow that Barrowman told her the doctor's signature was easy to copy.

She claimed she was raped by Barrowman in a doctor's room in Cornton Vale Prison and "didn't have much energy" because of medication she was on.

Barrowman is accused of supplying three women with drugs and raping them. He is also charged with attempting to rape one of the women and sexually assaulting a fourth woman.

He faces further drugs charges and behaving in a threatening or abusive manner towards one of his alleged victims. All the alleged offences are said to have taken place at Cornton Vale prison between February and March 2014.

During cross-examination by defence solicitor advocate Liam Ewing, the witness confirmed she had a clear recollection of Barrowman coming into her cell and talking to her about medication that would help her.

She claimed that in a later conversation, Barrowman said the doctor did not know she was being put on tablets.

She said: "He said something about Dr Craig doesn't know that I was put on it, he had actually done it himself and signed it himself because Dr Craig's signature is really easy, it's really just a tick."

Mr Ewing asked when the discussion about him forging the signature took place and she replied: "That happened after I got the medication."

In earlier evidence, the witness claimed she was attacked by Barrowman in a doctor's room and raped.

Barrowman denies the charges and the trial before judge Sean Murphy QC continues.