Last night Mr Abbott confirmed that DNA tests had established he was not the father. "It's a shock to me. I've gone through 27 years of life convinced that I was Daniel's dad, and it appears that's not the case," he told Channel Seven. "Of course, I'm disappointed. You don't live through these things for 27 years, you don't go through the excitement and the wonder of a reunion and then lose that and not be disappointed."

Daniel O'Connor's mother, Kathy Donnelly, had always believed that Mr Abbott, with whom she had a relationship when he was a teenage law student in Sydney, was the biological father. Five days after Mr O'Connor was born, in July 1977, Mrs Donnelly and Mr Abbott decided to give him up for adoption. Mr O'Connor's real paternity was confirmed last week through DNA testing involving Mr Abbott, and his biological father, whose identity has not been revealed.

The father contacted Mrs Donnelly last month to say he thought he might be Mr O'Connor's father. It is believed he thought Mr O'Connor bore a strong resemblance to his own children. It is believed that Mr Abbott suggested DNA testing to resolve the identity problem.

"I had an inkling that this might be the case about a fortnight ago," Mr Abbott said last night. "I had some confirmation that it was probably the case last week. I wasn't going to say anything about it. I really think this is a matter for Daniel, above all else. But the story's out. It's a shock to me. "I'm sorry that poor old Daniel has been dragged through the public spotlight as a result of a connection to me, which it now appears was never the case." The story of Mr Abbott's reunification with his son was additionally amazing for the fact that Mr O'Connor had worked alongside the minister as a sound engineer in the federal parliamentary press gallery for the previous three years.

Mr Abbott yesterday described the past few months as "a bit wild, frankly". "To find the boy that I thought I had all those years ago. To go through a reunion and now to lose him like this is pretty shocking and I feel a bit numb about it all.

"Truth is stranger than fiction. This story has certainly developed some pretty surreal twists. For Daniel and for Kathy I hope a continuing great story, but not one that will obviously involve me." After deciding he wanted to get in contact with his biological mother, Mr O'Connor contacted Mrs Donnelly by telephone on Christmas Eve last year. It was then that Mrs Donnelly told Mr O'Connor his real father was Tony Abbott.

On December 26, Mr O'Connor received a phone call from Mr Abbott. His first words to the minister were: "Thanks for having me." In January Mr O'Connor attended a barbecue at Mr Abbott's Sydney home with Mr Abbott's extended family and Mrs Donnelly's family.

Mr O'Connor later introduced his adopted parents to Mr Abbott and Mrs Donnelly. Mr O'Connor's adoptive father, John O'Connor, said he "felt very much an onlooker despite the sort of critical role and position that we the three of us have played in his life" when he learned who Daniel's real father was. Mr Abbott said he had spoken to Mr O'Connor since learning that he was not his real father.

"I did speak to Daniel once last week when we got the news that in all probability he wasn't my boy," Mr Abbott said. "It was something that, once Kathy had talked to me about it, we both decided that it was probably in Daniel's best interest if he knew who his dad was. The fact is he's a good kid. Kathy, his mum, is a great girl. I hope they have a great life, and I guess I'm just sad for him that he's been dragged through the media mill because of the connection to me, which it now seems didn't exist."

Prime Minister John Howard said last night the latest developments had not changed his view of Mr Abbott. " Although it's become a very public issue, because it involves a high-profile politician, it is still an intensely private matter," Mr Howard told Sky News. "Nothing that has happened alters my intense personal regard for Tony Abbott." Mr Abbott, a conservative Catholic who has spoken out against abortion, has endured years of Labor taunts about being the father of a love child. Mrs Donnelly and Mr Abbott have remained in regular contact over the past 27 years, believing they shared a son. Mr Abbott later married another woman to whom he has three daughters, while Mrs Donnelly, a West Australian artist, also married and had four children.

THE STORY SO FAR 1965

· Tony Abbott and Kathy Donnelly are primary school pupils at Holy Family Convent, Lindfield, Sydney.

1975

· Abbott dates Donnelly in year 12 at St Ignatius College. 1976

· Abbott begins law/economics degree at University of Sydney. July 26, 1977

· Donnelly gives birth to a boy. Five days later, she gives him up for adoption. Abbott sees the child briefly at birth. Donnelly and Abbott had separated two months earlier.

1980

· Abbott wins Rhodes Scholarship, leaves for Oxford. 1984

· Abbott returns, enters St Patrick's Seminary, Manly, to study for priesthood. He quits in 1987.

September 24, 1988

· Marries Margaret Aitken. They have three daughters. 1994

· Enters Federal Parliament. 2002

· Daniel O'Connor starts work as a sound engineer at ABC TV in Canberra press gallery.

December 24, 2004

· O'Connor contacts his birth mother, who subsequently tells Abbott. December 26, 2004

· Abbott phones O'Connor.

February 20, 2005

· Abbott and O'Connor's story becomes public. March 21, 2005

· Abbott confirms that DNA tests show O'Connor was fathered by another man.