A motorist who became intimate in his car with his girlfriend moments before he crashed has been found guilty of causing her death by dangerous driving.

Prosecutors said Minesh Parbat, 36, dropped his trousers and underpants at the wheel of his BMW Z3 to take part in a sex act with Lisa Watling.

Mother of two Ms Watling, 28, was found wearing only a T-shirt and bra following the crash, while the rest of her clothes were found in the car's footwell.

Members of the public discovered Parbat with his trousers and underwear around his ankles and his buttocks and penis exposed in the aftermath of the collision.

At Lewes Crown Court, Parbat told jurors that Ms Watling, a hair salon worker, had described feeling "horny" to him and invited him to pull down his trousers as he drove along.

Parbat, who lives in Gregory Close, Maidenbower, Crawley, West Sussex, was found guilty of causing death by dangerous driving after around half-an-hour of deliberation by jurors.

Adjourning sentencing to August 28 for pre-sentence reports, Recorder Peter Griffiths QC told him: "You have been, in my view, rightly convicted of this very serious offence.

"It is inevitable that you will lose your liberty. To prison you will be going. The question is what length." Parbat, who works in his mother's clothes shop, was freed on conditional bail.

During the trial, Parbat denied anything sexual had taken place as he drove at between 50mph and 60mph, adding that he had instead struggled to get Ms Watling off him before crashing.

He said he dropped his trousers and underpants as part of a "cheeky little dare" with Ms Watling and that "there was nothing sexual in it".

But prosecutor Philip Meredith told him: "You dropped your trousers and pants to play a part in a sexual act."

Parbat later added: "It's got sexual tones, but it wasn't sexual because nothing happened."

He claimed Ms Watling sat on the dashboard, then moved in front of him, obscuring his view, before he told her: "No, babe."

During a stormy exchange with Mr Meredith, Parbat was accused of shedding "crocodile tears" in court "to save your own skin".

Parbat suffered facial injuries in the crash and gave a positive blood test which showed 102 milligrams of alcohol per 100 millilitres of blood, the drink-drive limit being 80 milligrams.

Ms Watling died of her injuries after Parbat veered into the central reservation and then crashed into a fence on the A2011 in Crawley, West Sussex, at about 1.40am on March 9 last year.

Earlier in the evening, the couple had gone for a meal at TGI Friday's in Crawley before returning to Ms Watling's home in Kestrel Close, Langley Green.

After Parbat realised he had left his mobile phone at his home, the couple drove in his BMW to collect it and the crash happened as they returned to her house.

Parbat said Ms Watling suffered from intracranial hypertension, and suffered from headaches and was on medication including anti-epilepsy tablets.

He went on: "I loved her. Even from when I first met her, I had strong feelings for her. She was a beautiful person, inside and out. She just had something. She was special."