A WOMAN found out the man she had spent a lifetime calling dad was not her real father after she received a DNA kit for her 70th birthday.

Prue Heron, 72, a photographer from Hassocks, told Channel 4 News programme “DNA testing kits: family secrets revealed” of her shock.

And she predicted a big rise in the number of people discovering similar family secrets because of more and more buying DNA kits to discover their heritage.

DNA kits cost from about £50 and can offer basic details such as geographic heritage right down to names of people you are biologically related to. Most require those who use them to provide a saliva sample, which is then matched with DNA data.

Describing how she originally thought the present was a “lovely idea”, she revealed what had happened since the results stated a different man was her father.

She said: “I got the kit from my two nieces and sister for my 70th birthday. It was a lovely present and I just thought it would show my global origins.”

She initially did not question the results and it was only when she came to look at them again about a year later that she “realised it had another page”.

She said: “I realised there was a stranger in there and it really went from there. My sister did a test and the only person that we hadn’t got in common was my father and therefore my dad was not my biological father.’”

Describing the emotions at finding out she had grown up with a man who was not her biological father was hard to fathom, not least because they had looked alike.

She said: “It was an amazing shock. We were very close together, we loved each other.”

After discovering her sister was only her half-sister, she told The Telegraph earlier this year she decided she had to track down her real heritage on her father’s side, saying: “I can’t rest until I find out who my father was.”

She recruited a DNA detective and, after researching further, Prue eventually tracked down biological relatives including her cousins, although her real father had already died.

She said while her own discovery had been a big shock, such tests might offer “happy endings” for many people.

She said: “I think there’s about to be the biggest explosion on DNA testing and skeletons coming out of the closet and probably a lot of people are a bit worried about it. Before, people could go to their graves with a secret and now the secret may come out.”