Paddy Cannon has spent most of his life searching for his family.

Growing up, he knew "absolutely nothing" about his identity.

He didn't even know his mother's name until he was 22.

For more than 60 years, the Perth resident has been trying to find his mother and his birthplace.

Like many other child migrants, shipped to Australia from British orphanages, he has been hamstrung in his search by the scandalous lack of records kept by authorities.

Unwilling to give up, he travelled back to the United Kingdom several times to try to piece together the puzzle.

But often as one door opened, another one closed.

DNA matching a game-changer

Paddy spent years searching for his family ( ABC News: Chris MacGregor )

Now the 80-year-old wants to share his joy with the world.

Paddy has finally found his family — all 67 of them: The Derrigs of County Mayo, north-west Ireland.

"It was a shock for them and shock for me, but a happy shock," he told 7.30.

A few years ago, he enlisted the aid of the charity, Child Migrants Trust, which helped to put his DNA on an international database.

It was a game-changer.

"Lindsay rung me and said, 'Look, keep it under your hat'," he said. "We've got a breakthrough on the DNA."

The Trust tracked his family down to Ireland after his DNA matched that of a second cousin living in the US.

Then, a representative from the Trust travelled to Ireland to talk to one of his three brothers, Michael Derrig, face to face.

"I felt like saying to her, you have the wrong house here," Mr Derrig told 7.30.

"I couldn't believe it. We asked her, would she have a photo of Paddy Cannon?

"She showed us his picture and as soon as we'd seen it, we said right away … 'he's definitely a Cannon'."

Sent to Australia at 10 years old

Paddy Cannon (highlighted) watching two boys boxing at Clontarf Boys Town. ( Supplied: Paddy Cannon )

Paddy was just 10 when he was shipped with other child migrants to the notorious boys home, Bindoon, north of Perth, from an orphanage in Bristol in 1947.

He doesn't want to go into the detail of life at Bindoon but the physical and sexual abuse of some of the children there was laid bare at the recent royal commission into child sexual abuse.

Paddy Cannon's mother Catherine ( Supplied: Paddy Cannon )

Like many other child migrants, he was told he was an orphan.

He has since discovered he was born in Wales in 1937 to an unwed mother, Catherine, and was handed over to the Sisters of Nazareth when he was six weeks old.

At some point after, Catherine returned to her homeland in Ireland and married a local farmer, raising three more boys and three girls.

Mr Cannon never met his mother. She died in 1975, aged in her sixties.

But, he's been twice to Ireland to meet his siblings, and this month the family has been visiting him in his home state of Western Australia.

'We didn't know Paddy existed'

Paddy eventually visited his family in Ireland ( Supplied: Paddy Cannon )

Brother, John Joe, says meeting Paddy for the first time was like catching up with an old friend.

"A little bit of a shock at the time. Mam had never told anyone so we didn't know Paddy existed," he said.

"But after 15, 20 minutes, you got that feeling that you knew him all your life."

"He touches people," said niece Mary Derrig.

"He's kind. He's full of love despite the life that he has led. He seems to have totally accepted and forgiven."

It's been an emotional journey for Mr Cannon's newfound siblings.

They'll never know why their mother did not tell them about their eldest brother.

Michael Derrig fought back tears when trying to explain the mixed feelings the news had brought.

"I feel very sorry for her, to go through it all herself," he said.

"I feel sorry for her having to carry on. But they were the times.

"That's the bit of hurt that I have about it.

"The rest is all good."

'Mum knows that we are together'

Paddy Cannon with some of his Irish family in Perth. ( ABC News: Claire Moodie )

Paddy Cannon's story has been closely followed by the staff at Tuart Place, a support service in Fremantle for adults who have grown up in out-of-home care.

Mr Cannon helped to set up the governing body of Tuart Place and volunteers there, offering support to other former child migrants.

He's also been an advocate for the child migrants and campaigned for the Redress WA scheme.

Tuart Place director Philippa White said she was amazed by his persistence in finding his family.

"He would say, 'I'm going to find my family. I'm not giving up'," Dr White said.

"I wondered at times if it was the right thing to say to him, 'Paddy, do you think you should maybe accept that perhaps you are not going to find family?' Just from a sort of therapeutic point of view — but I'm glad that I didn't."

"It's one of those stories that lifts people's spirits because it's a story of hope, of someone who never gave up.

"Paddy is loved by his Tuart Place family because he is such a kind person and does so much for others.

"It's really nice to see something great happen to Paddy."

Mr Cannon says one of the most touching gestures by his newfound family has been the surprise addition of his name alongside his siblings on his mother's headstone.

"When I spoke to the family at the grave site, I said to them. 'Mum knows that we are together'," he said.

"That's given her peace in the next world."