The nightmarish real-life story of a mother who had to wait 18 YEARS to prove she had been given the wrong baby in a maternity ward mix-up

The question at the centre of a new psychological drama would strike fear into the heart of any parent: what do you do if you discover your child is not yours? Margaret took home Valerie, right, while Blanche was given Peggy, left It took 18 years for the truth about the girls, Peggy and Valerie, to come out, and while both have since died, their own daughters have now spoken for the first time, describing how the emotional shockwaves of that innocent mistake left an indelible mark on their families. Pictured, Margaret and Valerie in the late 1930s Blanche unwittingly took home a newborn she named Peggy, both pictured, and brought her up as her own with her husband Fred At one point Valerie confronted her 'mother', Margaret, and suggested that should there be a house fire, she would 'save the others before you saved me'. In an interview 40 years ago, Margaret described walking into Blanche and Fred Rylatt's living room after the girls' first birthday and knowing Peggy was her real daughter. Valerie, meanwhile, having eventually settled in Andorra with her second husband, Jim Cruickshank, returned to The new ITV thriller Playing Nice stars Downton Abbey's Jessica Brown Findlay, pictured, and charts the turmoil of two families who find out that their sons were swapped at birth Nottingham to give birth to her children, Jayne and Adam.