Sir Paul McCartney's long winding road to his ancestors

Although he is as Scouse as Lime Street and the Mersey, Macca has always been proud of his Irish heritage.

But when his brother, Mike McCartney, took a fresh look at the family tree he was amazed to find a Caledonian connection to throw into the mix.

The former frontman of the 1960s group The Scaffold found that the McCartney family took a long and winding route across the Irish Sea to Scotland before eventually settling in Liverpool.

The discovery has prompted Scottish Government genealogists to invite the McCartneys to head back north of the border to find out more about their Scots forebears.

McCartney made the find while compiling a book of photographic images of the Highlands, which will be exhibited in the Scottish Parliament next month.

He said: "Scotland is an area that has strong links with my family. In fact I have done some research and traced our roots back to the McIntosh clan. It seems my family came over from Ireland to Scotland about 150 years ago or so – before travelling down to Liverpool."

It is believed that the McCartneys' great-great-grandfather settled in Scotland in the mid-19th century.

There is evidence from other sources to support the idea that the McCartneys moved from Ireland to Scotland.

American-based family genealogist John McCartney, who specialises in the history of his famous surname, said members of the McCarthy Mor family of Munster left Ireland for Scotland around this time, with many of them starting a new life in Galloway.

Kirkcudbright resident and Beatles fan Sandra McCartney was tickled by the suggestion that she might be distantly related to Sir Paul.

She said: "It's a bit of a coincidence. When people hear my surname they often ask me if I am any relation to Paul McCartney. I usually laugh and tell them he's my uncle, but from what I hear I might not actually be that far off."

The General Register Office for Scotland urged Sir Paul and his brother to return north to investigate their Caledonian heritage further as part of the Homecoming 2009 celebrations.

A spokesman for the Scottish Government body said: "Our Scotland's People Centre staff would be delighted to assist Sir Paul or Mike McCartney in tracing their Scottish ancestors."

Mike McCartney's collection features 31 images of the north Highlands, including the world's shortest street, in Wick, the Dounreay nuclear plant, and a remote chocolate factory in Durness. One of the most rewarding parts of his Highland odyssey came at Castle of Mey in Caithness, where staff revealed that the late Queen Mother was a big fan of his 1967 hit 'Thank U Very Much' and enjoyed belting out the lyrics after evening refreshment.

He said: "Apparently, after dinner, Her Majesty would insist on going solo for the 'Thank U very much for our Gracious Queen' line at the climax of the record. I didn't have the heart to say that the actual words of my song were 'Thank U very much for our gracious team'."

The Merseyside-based photographer became fascinated by Scotland's far north during an earlier visit.

He said: "I was really struck by the place. The climate up there is very different, as are the people. These are folk who don't want to be at the centre of the universe. The things I saw when I was up there were incredible."