He had arrived in London during the '60s in the hope of making his fortune. Jack joined a wave of Irishmen who made the journey and he was soon making headway in the construction business. His work brought him all across Britain and gradually he lost contact with his family at home.
One morning last year, the telephone at the missing persons' section of the London Irish centre rang -- Jack's family wanted help in tracking him down. His brother was dying of cancer and had only months to live. Through the work of Sarah Goodall, the missing persons' co-ordinator at the centre, Jack (not his real name) was located and put in contact with his family.
He returned to Ireland in time to see his brother before he passed away and was reunited with the family he thought he'd never see again.
This story has been repeated countless times over the years with the London Irish centre missing persons' section dealing with well over 2,000 cases since it was established in the 1970s.
"We search for missing Irish people who are expected to be in England or Wales and deal with about 80 to 100 cases a year. At any one time we'd have at least 40 live cases to work on," Ms Goodall tells me at the centre's offices in Camden.
In the past 12 months, the missing persons' unit here has taken on 93 cases, with 68 of those referring to missing men. The youngest missing person over that time was a 22-year-old and the eldest was aged 83.
Of those missing in the 2011/2012 timeframe, only 22 could not be traced; it was discovered that 10 of those missing Irish had died. At least 11 were reunited with their families, while 14 turned down the opportunity to get back in touch with relatives in Ireland. The rest of the cases remain open.
"There's usually a catalyst that leads to the search, like someone has passed away or maybe their mother is seriously ill and they want to get all the children together. Sometimes it can be because someone has been left something in a will," explains Ms Goodall.
"Often a relative is found but they don't want to have contact, sometimes people who are missing want to stay missing."
On average, a quarter of cases result in an ideal outcome with the missing person being reunited with their family, but breaking bad news has become part and parcel of the job for Ms Goodall.
"We always warn people that you may not get what you're hoping for, but we hope they'll get something. Often I'll have to call a family and tell them the person they're looking for has passed away. Sometimes, though, that can bring closure to a family and help them move on with their lives.
"There must be nothing worse than not knowing what happened to someone who was once so close."
The service, which is free to use but costs £8,000 (€9,950) to run each year, uses a subsidiary of the NHS to conduct a search through health records in England and Wales.
They try to locate a person through his/her name and accurate date of birth. If an area where the missing relative last lived is provided, that can also help narrow the search down.
If the missing person is found, their GP will be contacted and they will then ask their patient if they want to contact the family in Ireland.
Only blood relatives and spouses are allowed to use the service and the missing persons' section at the Irish centre can't help in adoption cases.
With the Irish population in London growing and the number of cases arriving on Sarah's desk doubling over the past three months, it's clear this service is as vital now as it was when it was first set up five decades ago.
• If you want to search for a missing Irish relative in England or Wales, email email@example.com or call (00 44) 207 916 2222