The former mistress of a man accused of killing his children in a house fire has told a court how she and his wife used to alternate the nights they would sleep with him.

Lisa Willis, 29, said she would sleep with Mick Philpott one night and his wife Mairead, 31, would sleep with him the other night at the home they all shared with their children.

derby fire

Mick Philpott (second from left) and wife Mairead (second from right) appear at Nottingham Crown Court along with Paul Mosley (right) ahead of their trial

She told Nottingham Crown Court: "We took it in turns, we never had all three of us together."

She went on: "We would take it in turns at night so one night it would be me, one night it would be Mairead."

Miss Willis said the children slept upstairs and this arrangement continued until they bought a caravan which stood on the driveway of the house.

Derby House Fire: Mick And Mairead Philpott On Trial For Blaze That Killed Six Children

The woman who would be sleeping with Philpott on any given night went to the caravan with him, while the other woman slept inside with the children.

Miss Willis told the court about the domestic arrangements at 56-year-old Philpott's manslaughter trial.

He denies six counts of manslaughter in relation to the deaths of the six children.

mick mairead philpott

Mick Philpott and wife Mairead following the fire at their home which claimed the lives of six of his children

His wife and a third defendant, 46-year-old Paul Mosley, also deny the same six charges.

Mick and Mairead Philpott's children - Jade, 10, and her brothers John, nine, Jack, eight, Jesse, six, Jayden, five, and Duwayne, 13 - all perished after the fire which engulfed their home in Victory Road, Allenton, Derby, as they slept in their beds in the early hours of 11 May last year.

It is alleged by prosecutor Richard Latham QC that the Philpotts and Mosley started the fire in a botched plan to set Miss Willis up as the culprit after she and her five children, four of whom were fathered by Philpott, left the relationship.

Miss Willis, who gave evidence to the court from behind a screen, said she met Philpott when she was 17, and that he was a friend of her sister's.

She already had a young son with another man and was living in a two-bed council house at the time but was hoping to move to larger accommodation, which she was struggling to get.

After getting better acquainted with Philpott he suggested she moved in with him and his wife, though they were not married at the time.

The couple had a son and a daughter and Miss Willis told the court that when they decided to marry she was a bridesmaid at their wedding.

Her relationship with Philpott became sexual "weeks" after she moved in to the Victory Road council house, and it was something which did not bother Philpott's wife.

"Mick said he asked Mairead about it, if she was okay about it, and apparently she turned round and said she was fine.

"He asked her in front of me as well and said, 'I've asked you about Lisa moving in' and she said, 'Yeah, I'm fine about it.'"

Mr Latham put it to her: "There's a difference between you moving in and having a sexual relationship."

Miss Willis replied: "She was fine."

She told the court about an incident of violence relatively early on in their relationship, when she claimed Philpott repeatedly hit her on the legs, back and arms with a piece of wood.

The argument started when he questioned her about who was the father of her child, she said.

"He just kept saying 'no, it's not true,'" she said.

She added she was "shocked and disappointed" after the incident and that "if we had a fall out he would bring it up again".

Miss Willis told the court there were other incidents of violence but they were infrequent and usually stemmed from when Philpott could not see his children from a previous relationship.

She told the jury he grabbed her once claiming she had hit Jade and, in a separate incident, threw a cup of coffee at her.

Christmas time and birthdays were often "upsetting" because he was not with all of his children, she said.

Philpott controlled her finances - her wages as a canteen assistant, then as a cleaner, and her benefits went into his bank account - and her comings and goings were monitored by him.

"I could not go out shopping on my own, I could not go into town.

"He would ask me questions - where I'm going, how long I'll be and what for."

Mr Latham asked her: "Did you have free rein to leave the house if you wanted, or not?"

She replied: "I could leave if I wanted to but I did not go out because I was so sick of all the questions and answers of when I'll get back, so I did not bother."

Miss Willis told the court that unemployed Philpott, who she said did nothing round the house except watch television, drove her to work and picked her up, and constantly accused her of having affairs with colleagues.

She got a job as a cleaner, working from 6am until noon, and Miss Willis told the court: "He said I was selfish for getting a job from 6 o'clock in the morning."

She told jurors that when she was pregnant with her first child with Philpott, he asked her: "How do I know it's mine?"

None of their four children were planned, she said, and the relationship between the Philpotts was continuing.

Mr Latham asked her: "The same time as you're gradually having those children what was happening as far as Mairead was concerned?"

"Mairead was having children as well," Miss Willis said.

She told the jury Philpott often said he wanted to divorce his wife and marry Miss Willis instead.

Mr Latham asked her if she was content generally with domestic arrangements.

"Were you happy as time went by with the regime?", he asked.

"No I was not happy."

Mr Latham also asked Miss Willis if she was happy with the physical side of the relationship.

"I was to start with but towards the end I just made excuses up all the time," she said.