One of Scotland’s most ancient clans has appointed its first chief in more than 300 years.

John Michael Baillie-Hamilton Buchanan has assumed the chiefship of the Clan Buchanan after his claim was formally upheld by the Lord Lyon King of Arms, the head of Lyon court, which regulates Scottish heraldry.

The role was last held by his ancestral kinsman John Buchanan until his death without a male heir in 1681.

Buchanan, who is the manager of Cambusmore estate, near Dornoch in Sutherland, and will now be known as The Buchanan, said that he was “honoured and proud” to assume the chiefship. “There has not been a chief for a very long time - over 337 years - but there is a thriving community of Buchanan clansmen, clanswomen and septs around the world,” he said.

Adding that it had been a “long journey” to prove his family’s lineage, Buchanan thanked the genealogist and fellow Buchanan clansman Hugh Peskett, who traced his ancestors back to 1370 and established references in 300 documents from around the world to verify the claim.

Buchanan explained: “We first approached the Lyon court informally over 20 years ago and it has taken decades of genealogical research to back up our claim.”

Peskett, who also traced the Irish lineage of the former US president Ronald Reagan in the 1980s, described it as a historic moment for Clan Buchanan. He became a genealogist 50 years ago, after his grandmother encouraged him to find the rightful Buchanan chief.

He said: “As a clansman of the Clan Buchanan, it was absolutely fascinating to delve into the history and ancestry of one of the oldest clans in Scotland. Tracing hundreds of years of lineage and unpacking the secrets of the past is no mean feat. My research took decades to compile and unequivocally confirms the chiefship claim.”

Traditionally, Clan Buchanan can trace its line back to the early 11th century, when an ancestor received lands around Loch Lomond from Malcolm II for services in fighting the Danes.

It now has several million members across Britain, the US, Canada, Australia, New Zealand and elsewhere.

The Clan Buchanan Society International previously flew a banner at the Highland games, which featured a lion rampant with tears of sorrow to represent the sadness of clansmen without a chief.