LONDON — Mick Philpott presented himself as an amiable rascal with an unorthodox lifestyle and a rambunctious brood of children — 17 in all, with five women.
Yet the Englishman’s ramshackle existence took a horrifying turn when he and his wife set a fire that killed six of their children. Prosecutors said it was an attempt to influence a custody battle that ‘‘went disastrously and tragically wrong.’’
The May 2012 deaths and the twisting saga that ensued have shocked Britain and sparked debate on everything from sexism to Britain’s welfare system.
A judge said she would sentence Mick and Mairead Philpott on Thursday for their manslaughter convictions in the deaths of the six children, ages 5 to 13.
Prosecutors said the couple hatched a plan to start a gasoline-fueled fire and then rescue the children, pinning blame on Philpott’s mistress so he could gain advantage in their child custody battle.
The plan went wrong within minutes, because the fire was bigger than expected and the father was unable to smash a window to get in, police said.
The couple and a friend who helped them, Paul Mosley, were all convicted of manslaughter this week at England’s Nottingham Crown Court.
Before the fire, Philpott, now 56, was a local celebrity — nicknamed ‘‘Shameless Mick’’ after a television program about a disreputable working-class clan — who had appeared on a daytime talk show defending his lifestyle. In 2007, a Conservative lawmaker stayed at his home for a week as she filmed a critical documentary about Britain’s welfare system.
The jury — and the nation — got a close-up look during the trial at Philpott’s messy life with his 32-year-old wife, his girlfriend, and as many as 11 children in a three-bedroom public housing property in Derby. They heard of threesomes and public sex, of Philpott’s controlling behavior, and of his bizarre claim that he had not washed for 12 weeks before the fire.
Shortly before the fire, girlfriend Lisa Willis moved out, taking her five children with her. Philpott’s five children with Mairead and his wife’s 13-year-old son from a previous relationship remained in the home and died in the blaze.
After the fire, the Philpotts made an emotional appeal on television, with Mick describing how he had battled the flames to try to save his children.
But police soon grew suspicious of the couple’s erratic behavior and bugged the hotel room where they were staying. The jury was played recordings of Philpott asking his wife: ‘‘Are you sticking to the story?’’
The couple was arrested two weeks after the fire and charged with murder, later downgraded to manslaughter.
‘‘It was started as a result of a plan between the three of them to turn family court proceedings in Mr. Philpott’s favor,’’ said Crown Prosecution Service adviser Samantha Shallow. ‘‘It was a plan that went disastrously and tragically wrong.’’
Steve Cotterill, the assistant chief constable of Derbyshire Constabulary, said it had been ‘‘one of, if not the most, upsetting cases any of us has ever investigated.’’