being taken to his execution, 1753; he was allegedly captured using information provided by MacDonnell At some point, he was recruited by
Henry Pelham as a Hanoverian
mole inside the Jacobite movement known as "Pickle"; this remained secret during his lifetime but his identity was confirmed by the Scottish historian
Andrew Lang in 1897. His reasons appear to have been a combination of poverty, resentment at not being compensated for his losses and a liking for the art of deception. His major coup was providing information on the 1752
Elibank Plot, which led to the arrest in March 1753 of Dr.
Archibald Cameron, who had escaped into exile after
Culloden. He was tried and executed in June but using the warrant issued in 1746, supposedly to conceal the source of the information. The betrayal of the plot also coincided with the resumption of Prince Charles's affair with
Clementina Walkinshaw, whom he first met in 1746; by coincidence, one of her sisters was lady in waiting to the
Dowager Princess of Wales and it was widely believed she was the informer. It has also been suggested MacDonell "helped himself to the
Loch Arkaig treasure", a consignment of gold coins provided by the French in June 1746 to finance the Jacobite war effort. Cameron's explanation is not complete but since MacDonell was in prison at the time, he was unlikely to have a better idea of its location; modern-day treasure hunters have yet to find any trace of it. In 1754, Pelham's death ended MacDonell's career as a government informer and he succeeded his father as 13th
Chief of
Clan MacDonald of Glengarry. He returned home, although Invergarry Castle had been heavily damaged by government troops after the 1745 Rising and, despite his secret income as a spy, he could never afford to restore it. He never married and on his death in 1761, his nephew Duncan succeeded as 14th chief of Glengarry. ==In popular culture==