A British businessman has been jailed for 20 years for bludgeoning his fiancée to death after a row in a luxury French hotel.

Ian Griffin, 45, was found guilty by a Paris court last night of murdering Kinga Legg, 36, a Polish-born millionaire at a suite at the five-star Bristol hotel in Paris, in May 2009. The jury rejected his defence that he has no memories of the violent killing.

Legg’s naked body was found lying in a three-quarters filled bath in the blood-stained suite, which investigators described as a scene of frenzied violence. She had suffered 100 injuries including a massive blow to the head.

Griffin, who admitted being addicted to alcohol and anti-depressants at the time, had left the hotel the day before staff made the grim discovery.

The court heard he had made strenuous, but unsuccessful efforts to clean the £1,000-a-night room. He phoned reception twice to say they would be extending their stay, placed a Do Not Disturb sign on the door, drank three coffees and told staff his wife was sleeping before fleeing in his Porsche 911.

In Britain, a police manhunt was launched and Griffin was found sleeping rough in a tent in a wood in Cheshire. He was later extradited to France.

During the five-day trial, Griffin claimed his mind went blank and he could remember nothing of the evening that left his partner dead and room 503 at the Bristol, a stone’s throw from the British embassy in Paris, trashed. He had suggested Legg’s death was “probably” accidental and that she may have fallen backwards, banging her head on a low table.

But prosecutors cast doubt on his memory loss claim, pointing out that in an interview with the Mail on Sunday in May 2013, Griffin said: “‘She fired a stun gun disguised as a stick of lipstick at me and then punched me in the face, catching me with a ring. I tried to defend myself and she fell over and banged her head on a coffee table.

“After she calmed down, she went to bed. Toxicology tests later showed she had taken 30 medications, including a Polish blood-thinning drug that would have prevented her blood from clotting and caused internal bleeding.”

Legg, who was born Kinga Wolf, met Griffin in Monaco in 2008. They were planning to marry in August 2009, but Warrington-born Griffin admitted he had been also seeing Tracy Baker, 34, who appeared on the British television show Dragons’ Den. Griffin and Baker now have a son and live together in France.

The prosecution portrayed Griffin as a violent man, particularly after he had been drinking, and recorded how he once drove his Mercedes through the front door of Legg’s mansion in Oxshott, Surrey. He was said to have attacked her a month before she was beaten to death.

Griffin’s defence team attempted to blacken Legg’s name, describing her as prone to jealous, drunken rages that could be “very, very violent”.

However, Jane Carrigan, one of Legg’s close friends, told the hearing she had never know the dead woman to be violent.

“On one occasion, Kinga phoned me to say she had been badly beaten by Ian and was in the bath trying to recover. She told me that he had driven his Mercedes through the front door of the rented £5,000-a-week house, then he beat her and left. This was approximately one month prior to her death.“I was so worried about her, I asked her to contact the police and an ambulance to see what state she was in because the next time she may be dead. She didn’t want to do this. The next thing I heard she was dead.

“Kinga was not aggressive. In all the years I’ve known her, I’ve never seen her hurt anyone. She was one of the kindest, most generous people I have ever met.”

Legg, who made her money running a successful tomato export company, received 100 blows to the head, face and body. Griffin said the couple had rowed over sex in a nearby restaurant, but his memory went blank over what happened later in the hotel room. He said he woke up the next morning to find the room trashed and covered in blood.

Investigator Xavier Le Noë told the court that the crime scene “sweated a kind of fury”. The room, he said, had been ravaged; the walls, bed and floors were covered in blood and there was broken glass and furniture.

Griffin, a former rugby player weighing 90kg, suggested he was probably acting in self defence against Legg, who weighed, he estimated, about 51kg. Griffin said his fiancée was incredibly strong and sporty despite her slim appearance.

The prosecutor, Philippe Courroye, told the court the intention to kill was clear. He said Legg’s body had more than 100 bruises – 17 on the head, 33 on the thorax.

“She had them from head to toe,” Courroye said. “If there was so many injuries, it’s simply because he wanted to kill her. The autopsy revealed the force of the blows. This was a tortured body.

“She was beaten to death. This is a type of crime that has a name: it’s called violence against women.”

He described Griffin as a “kind of gigolo – a supposed businessman without any official income who had always lived off his parents”.

Courroye was sceptical of Griffin’s memory black hole: “This fairytale of amnesia is impossible to believe.”

In April 2009, Legg wrote an email to Griffin in which she spoke of her fears over his violence.

“I never had anyone who beat me, who threw me down on the ground. I’m scared you’ll kill me one day.”

Courroye warned the jury about being taken in by Griffin: “He’s trying to mystify you. He’s lying to the whole world and in his lies he’s killing her a second time.”