I found this charming tune in the October 1756 issue of The Universal Magazine. The title refers to William Blakeney (1672-1761), commander of the besieged British garrison at Fort St. Philip on the Spanish island of Minorca in 1756. Admiral John Byng was sent to relieve the fort, but his botched effort and failure to engage the French eventually led to his famous court-martial and execution by firing squad. Although Blakeney was forced to surrender, his gallant defense of the fort, which though lost, was in ruins and of no use to the French, made him a hero at home. He was made a baron in the Irish peerage.
The original tune is in B flat and really does sound better (to my ear) in that key, but I have transposed it here so it can be played on flute. The variations below are my own.