Alestair Ruadh MacDonnell lived from 1725 to 23 December 1761. He was a Jacobite member of the Scottish nobility best remembered as the man usually believed to be "Pickle", the codename of a government spy who was part of Prince Charles Edward Stuart's Jacobite entourage in exile on the continent. The wider picture in Scotland at the time is set out in our Historical Timeline.
The MacDonnells (or Macdonells) were a branch of the Clan MacDonald. Alestair's father was John MacDonnell, the 12th Laird of Glengarry, a man with a reputation for violence who allegedly starved his first wife, Alestair's mother, to death on a Hebridean island. Alestair fled from his father to France at the age of 13 in 1738, and while still very young became a junior officer in the Royal Scots, a Scottish (largely Jacobite) regiment serving in the French Army. By the age of 18 he had risen to become a company commander in the Royal Scots, and the following year, 1744, he was sent to Scotland as a Jacobite agent preparing the way for the planned return of Prince Charles Edward Stuart, which took place in 1745.
During the 1745 Jacobite uprising, Alestair Ruadh MacDonnell returned to France before attempting to sail to Scotland with his troops. His ship was intercepted by the Royal Navy, and MacDonnell was imprisoned in the Tower of London. After nearly two years he was released and expelled to France. By now Alestair's family estates had been confiscated by the Government because of their Jacobite sympathies and he found himself in poverty.
In 1749 Alestair Ruadh MacDonnell visited London, and according to the author Andrew Lang, it was during this time that he reached an agreement with the Hanoverian government to spy on Prince Charles Edward Stuart and the Jacobites on the continent. This he did, communicating with London under the codename "Pickle", and his intelligence led to a number of Jacobites in England and Scotland being arrested, most notably Dr Archibald Cameron of Locheil, who became the last Jacobite to be executed in 1753.
Some Jacobites were said to have had doubts about Alestair Ruadh MacDonnell's loyalty, but he remained trusted by Prince Charles Edward Stuart until his return to Scotland in 1754 after his father's death. MacDonnell's inheritance of the previously confiscated family estates was presumably the payback for the considerable services he had rendered to the government. MacDonnell lived long enough to become a deeply unpopular landlord in Glengarry, dying at the end of 1761.