A MAN'S mobile phone video of a prostitute performing sex on him was just the evidence that police needed when she and her boyfriend later robbed him of £90.

Stewart Mackay recorded the act in his home after 21-year-old Petrina Patterson stopped him in the street and asked if he was looking for business.

Afterwards he asked her to stay for a little longer, and she said she must contact her next client to say she would be late.

They were sitting on the sofa when her boyfriend Bryan McDermott, 26, burst brandishing a knife shouting "Give me your money".

Mr Mackay handed over his wallet, credit cards and mobile phone which carried his PIN number.

His bank card and phone were passed to Patterson who withdrew £90 from a cashpoint at 5am, but she failed to get another £100 failed. When she returned to the house she handed back the card and phone.

Mr Mackay called police and told them that he had recorded the £20 sex act, said prosecutor Sharon Elves. Officers recognised the single mum and McDermott, who was also arrested.

The couple were both drug addicts when they targeted Mr Mackay last September, Teesside Crown Court was told.

Robin Turton, defending, Patterson, said that she had since quit prostitution and was determined to stay out of trouble.

Duncan McReddie, for McDermott, said he was anxious that she did not suffer punishment for what was entirely down to him.

The Recorder of Middlesbrough Judge Peter Fox QC told them: "The fact that you had an addiction to drugs is no excuse."

McDermott of Stanmore Avenue, Middlesbrough, who pleaded guilty to robbery was jailed for five years and Patterson of Boynton Road, Middlesbrough, who admitted theft was jailed for nine months.