The police inspector gifted with Stone of Destiny fragment after daring 1950 Westminster Abbey raid

As the authorities hunted for the sandstone block, Det Insp Kerr worked to uncover the conspiracy and identified one of those involved – only for the artefact to be handed back at Arbroath Abbey in April 1951.

Now, a research project has found the Glasgow Police inspector, who went on to become chief constable of Dunbartonshire Constabulary, accepted a small piece of the stone as a gift some years later.

Professor Sally Foster, from Stirling University, has been working to trace the stories of more than 34 fragments of the stone created when it was repaired in secret by stonemason and nationalist sympathiser Bertie Gray.

Some of her research was published in an academic journal earlier this month, but Prof Foster is continuing to hear about new fragments as a result of people coming forward to share their stories.

The stone split in two as the students removed it from Westminster Abbey and Mr Gray was trusted with its repair.

Mr Gray’s work involved inserting metal rods into the stone to bring the two pieces together, a process that produced a number of fragments which he kept – carefully numbering and distributing many of them in secret.

Some pieces have been kept hidden as family heirlooms, being brought out for special occasions but rarely seen in public.

A note from Det Insp Kerr was uncovered by Prof Foster from a document kept at National Records of Scotland.

Her research has led her to believe Mr Gray may have given him the fragment at a dinner in 1956.

In the 1973 document, Det Insp Kerr says: “When I was formally presented with my ‘piece’ of the Coronation Stone by those who engineered and carried out its removal from the abbey, I laughingly expressed scepticism about its genuineness as the repaired stone was apparently intact.

“Gray then explained that in the process of ‘tunnelling’ for the rods, seven tiny pieces were removed and carefully retained to be presented to certain individuals, of whom I was one.”

Despite Mr Gray’s explanation to the police officer, Prof Foster said she believed there were far more than seven fragments that were distributed among supporters of the students and the wider Scottish independence movement.

None of the students involved in the raid was ever prosecuted, which may explain why Det Insp Kerr was confident to accept the gift.

Prof Foster said: “Detective Inspector Kerr was in charge of the Glasgow police investigation into the loss of the stone, liaising with Scotland Yard.

“Ultimately, he gets friendly with the students and their parents and Bertie Gray, and they all stay in touch.”

Prof Foster added: “He [Kerr] got given a fragment, and he accepted it.”

The most likely occasion for this gift would have been a dinner in 1956 in honour of Kerr and his wife – the point at which he became chief constable.

This event was attended by Mr Gray and the father of Alan Stuart, one of the students who took part in the Westminster Abbey raid.

Kerr’s missive from 1973 came as the Home Office sought to verify the authenticity of the stone, which was handed back at Arbroath Abbey.

Other fragments from the Stone of Destiny that were created during Mr Gray’s repair include an inch-sized piece that was gifted to Alex Salmond by Sir Neil MacCormick and kept at SNP headquarters.