A jealous martial arts expert who strangled his partner after learning she planned to leave him for another man was found guilty of murder today.
Alan Jermey was "obsessive" about Mercedes executive Kirsty Wilson, the mother of his two children, and could not stand to let her go.
Jermey, a car salesman with a black belt in kung fu, used his skills to throttle her, leaving few external injuries.
He set her body alight to try to make it look as though she had died in a fire but the blaze failed to take hold.
The killer hatched a cold-blooded plan to kill her after learning she planned to leave him for her married boss Simon Goddard.
Miss Wilson signalled an end to their nine-year relationship when she told him: "I can't see us spending the rest of our lives together."
He secretly ordered a 100,000-volt stun gun over the internet so he could knock her out before killing her.
After pouring petrol over her, he arranged her body to make it look as if it had been set alight and clambered on to an extension roof with their two daughters as one of them cried: "I want mummy."
Jermey, who worked for a car firm near Heathrow, claimed in court that he had gone to bed early and left Miss Wilson downstairs when he was woken by an explosion and was prevented from saving her by thick black smoke.
But when firefighters arrived, they found there were only a few wisps and noticed he seemed calm and unconcerned about what had happened to her after they rescued him and his daughters.
Now the killer faces a life sentence after an Old Bailey jury rejected his story and found him guilty of murder.
Miss Wilson's parents Peter and Sandra Wilson, who both wept as they gave evidence at the trial, described her as popular and beautiful, and "the kind of woman who turned heads".
They said the real victims were their two granddaughters, who had been deprived of their mother.
Mother Sandra Wilson said Jermey was "obsessive" about her daughter.
"When I would say 'that's a pretty girl on the television', he would say 'no, she's not as nice as Kirsty, there's nobody as nice as Kirsty'. He thought she's really something special," she said.
Mr Goddard, who had already left his wife and two children for Miss Wilson, said they were "very much in love" and planned to marry.
He said: "I still find it hard to accept that all of our dreams and plans for the future will never materialise."
When Miss Wilson told Jermey in May last year that she planned to leave him, he at first seemed to have calmly accepted it.
They stayed together in the house and made arrangements for the split but cracks began to appear in the facade and one night she found him crawling on the floor looking at her mobile phone.
Jermey, who was also several thousand pounds in debt, killed his partner in August, the night before their property was due to go on the market.
Sarah Forshaw QC, prosecuting, told the jury: "The time was fast approaching when she was going to leave him.
"That night, when the children were upstairs asleep, he killed her. He arranged her dead body on the floor. He went out to the garage where he kept petrol cans for the lawnmower.
"He poured petrol over, particularly over her head and her neck and he set fire to her.
"He was particularly anxious that he may have left signs around her that identified himself as her strangler. He expected the fire to take hold immediately and for the house to go up in flames. The fire never really took hold."
Detective Inspector Paul Monk said: "Jermey was consumed with jealousy and rage. He violently murdered the mother of his children and set fire to her, hoping that their family home would go up in flames, and crudely covered up the killing.
"He may have perversely believed that by taking Kirsty's life he could ignore the collapse of their relationship and retain full custody of their children. In fact, his wicked act has deprived two young girls of both their parents."
Jermey was remanded in custody to Monday when he will receive a life sentence after the judge decides on the minimum term he should serve.
Prosecutor Miss Forshaw told the court that, after Miss Wilson said she was leaving him, Jermey desperately tried to win her back.
He became a "model partner", giving up his martial arts training in the evenings to come home early and make dinner for her.
Jermey also wrote letters and postcards to her, describing his feelings and urging her to give the relationship another chance.
Miss Wilson, the youngest of three children, was originally from Bradford, West Yorkshire, and had trained as a teacher in Derby before going to work for a Tony Purslow Mercedes dealership in Basingstoke, Hampshire.
She met Jermey in 1999, and they bought a house together in 2000 before moving to their latest address in Greenmeads, Woking, Surrey, in 2004.
Miss Forshaw said of Miss Wilson: "She was a popular woman and good mother and very attractive."
She began an affair with Mr Goddard while away on a work course in spring 2007 and by the following year he had left his wife and children and they were planning new lives together.
Early on in the liaison, Jermey discovered a text message on her phone from Mr Goddard saying: "I wish I was there with you now" but accepted her explanation that it was "just some flirtatious fun".
However, in May last year, she told Jermey their relationship was over, although she did not reveal the full extent of the affair and wanted to spare his feelings by letting him down gently.
She was also frightened about what his reaction might be and she and her lover joked that Jermey might go round and beat him up.
Miss Wilson encouraged Jermey to go on dating websites and he claimed in court that he slept with three women he met online.
She had not told her partner she was already sleeping with Mr Goddard but said they planned to spend the night together at a party which was coming up a few days after the murder.
"Once public events started happening, once the house was up for sale, once Kirsty was in an intimate relationship with this man, Mr Jermey knew there was no turning the clock back," said Miss Forshaw.
Jermey had trained in martial arts for 30 years and was an expert in both kung fu and Taekwondo.
He ordered the stun gun from Germany over the internet in Miss Wilson's name. Also in the package were a CS spray and pepper spray and a 21in extendable metal baton.
When she found out about the delivery and asked him what it was, he at first said it was boxing equipment and then claimed the package contained pornographic DVDs.
On the night of the murder, Jermey called emergency services after starting the fire but it was two minutes into the call before he mentioned someone else was still inside the house.
Investigators found there had been no forced entry and valuable items had been left lying untouched on work surfaces.
Miss Wilson's body seemed to have been arranged to make it look as if she had fallen asleep watching television.
A post-mortem later revealed she was already dead when the fire started as there was no smoke in her lungs.
The fire had failed to conceal bruising to her neck although a pathologist said there were remarkably few signs of external injury.
There was also no evidence that she tried to fight back - investigators would have expected to see marks left by her long fingernails as she tried to pull her attacker's hands away from her neck.
Miss Wilson was found wearing only her knickers and socks, smelling of petrol - her other clothes having melted away.
A neighbour saw Jermey standing on the flat roof of an extension at the back of the house and one of the girls crying "I want Mummy".
Juliet Monk said the area was normally "very quiet".
"In the 14 years that we were there, there was only the odd misdemeanour that happened," she said.