A daughter who agreed to have a surrogate baby for her mum changed her mind and decided to keep the child.
The daughter impregnated herself with Mark's sperm using a syringe normally used to give medicine to babies.
But as the baby grew inside her, Leanne decided she couldn't bear to give her up. Now the family are involved in a bitter feud over Judith and Mark's involvement with baby Mollie, who is now 19 months old.
Talking exclusively to the Daily Mirror, Leanne, from Wallsend, North Tyneside, said: "What it came down to was that the bond with my baby was stronger than the bond with my mum."
The surrogacy pact was made in the car park of the mortuary at Newcastle's Royal Victoria Infirmary in October 2011, after Judith miscarried her son, Braydon, at 22 weeks, ending her dreams of a little brother for the youngest of her four daughters Megan, seven.
Leanne, who also has a four-year-old son, explained: "Mum was desperate for another child so that Megan would have a brother or sister around her as she grew up.
"I was worried because she has a history of premature births and Megan was born at 27 weeks weighing only 2lbs 2ozs.
"But Mum was determined to try for another and when she and Mark couldn't conceive naturally they went for IVF at James Cook Hospital in Middlesbrough.
"Even though I was worried I was really pleased for them when they fell pregnant and I shared in their grief when Mum miscarried. It was a terrible time. We all went to the hospital's Chapel of Rest to say a final goodbye to Braydon.
"As we left and stood in the car park I couldn't bear Mum's tears and I said to her, 'If you want to try again I'll help you, I'd be a surrogate for you if you wanted me to'.
"It was a spur of the moment offer made at a time of high emotion. But I meant it, I really wanted to help them."
After Leanne became pregnant with Mark's sperm, the delighted family prepared for the new arrival into their lives.
But all that changed in July 2012 when Judith and Mark paid for a 4D scan, which would reveal the sex of the baby.
Leanne said: "The scan was very detailed and the baby became very real to me. When we were told it was a little girl, I felt the first pull of maternal love for my baby and at that point a tiny doubt crept in but I pushed it aside."
And over the next few weeks Leanne's bond with her baby grew stronger and stronger and she began to wonder whether handing her over to Judith was the right thing to do.
She told the newspaper: "I spoke to one of my friends about the way I was feeling and she told me, 'She is growing inside you, you have that bond and you can't just switch off your feelings.'
"That was exactly the way I felt and although it was a terrible dilemma I knew in the end that I just couldn't hand over my baby to Mum."
Leanne went to see a solicitor who drafted a letter to Judith explaining that Leanne had changed her mind about the surrogacy agreement - which was never formalised legally - and would be keeping the baby. Judith tried pleading with her daughter to reconsider, but Leanne's mind was made up.
Mollie was born on November 15th 2012 weighing 8lbs 11ozs and Leanne was joined in the delivery room by her elder sister Emma.
At first, following Mollie's birth, Judith and Mark came to see the baby, even though the couple realised she would never be theirs.
But as weeks passed the relationship became more strained and Judith's anger towards her daughter grew.
The relationship between Judith and Leanne has now completely broken down and neither Judith nor Mark has seen Mollie since the end of March.
Leanne says she wants neither of them in hers or Mollie's life, but she still believes they ought to pay towards the little girl's upkeep.
She said: "They agreed to pay for nappies for Mollie, which amounted to about £10 per week.
"I had to go to the Child Support Agency to get proper maintenance payments for her and that is now being put in place. In the end I have my daughter's best interests at heart and I have to make sure she is being properly looked after.
"This has caused a split between myself and my mum that can never be healed now but every time I look at my beautiful little girl and feel that surge of love for her I know I made the right decision."
Judith told the MIrror: "What Leanne has done has left us completely devastated and now we don't see the little girl who was going to be our daughter at all.
"Leanne only thinks about herself. She wanted a baby but didn't want a man and now she has her wish. She went back on her word and it has ripped this family apart."
More on Parentdish: My husband's ex-wife offered to be my surrogate
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