A woman who doused a bed in petrol and set it alight while her lesbian former lover lay naked with a new girlfriend is facing a "substantial" jail term after being found guilty.

Jealous Sarah Metcalfe, 46, of no fixed abode, discovered her ex-girlfriend Katie Wrigglesworth in bed with Emma Shakesheff, in a caravan she owned at Goldsbrough Mill Farm, near Knaresborough, North Yorkshire.

Leeds Crown Court heard Miss Metcalfe set fire to the bedroom in a desperate bid to stop them having sex on July 20, last year.

The pair were initially trapped, but escaped through a window.

Ms Wrigglesworth, 26, suffered 40 per cent burns to her arms, legs and body and had to spend ten weeks in hospital. Ms Shakesheff, 32, sustained extensive second degree burns to 44 per cent of her body and spent six weeks at Pinderfields Hospital, in Wakefield.

Miss Metcalfe had pleaded guilty to grievous bodily harm (GBH) earlier in the trial, but insisted it was an accident.

Mr Justice Royce discharged the jury after they failed to reach a verdict on two counts of GBH with intent after more than five hours of deliberations.

Miss Metcalfe, whose son was watching from the gallery, then pleaded guilty to a charge of arson being reckless as to whether life would be endangered.

Sentencing was adjourned for reports, but Mr Justice Royce warned Miss Metcalfe that she faced a "substantial term of imprisonment".

During the five-day trial, the court heard how Miss Metcalfe's and Ms Wrigglesworth's four-year relationship had ended last June, but the pair continued to use the caravan.

Miss Metcalfe described how her heart "dropped to her socks" when she walked in on her former lover caressing a new girlfriend.

She became embroiled in a heated argument with her ex, who stormed off, saying: "I've had enough of this, I'm off to bed to make love to my bird."

A few moments later, she saw the pair having sex through an open bedroom door.

She later told police that her former partner had been "rubbing her nose in it" and grabbed a petrol can from the caravan.

She told the court she poured the petrol over the bed and just "wanted them to stop".

Miss Metcalfe, who had downed six or seven pints of beer and a few whiskies, then flicked a lighter and the room became engulfed in a wall of flames.

She went outside and helped pull Ms Shakesheff out of a window, through which Ms Wrigglesworth had already escaped, and went to call the emergency services. The victims, who were in court, are still recovering from their injuries.

Miss Metcalfe was remanded in custody for sentence at a later date