A British Ambassador leaving his post was encouraged to write what was known as a valedictory despatch, to be circulated to a small number of influential people in government. This was the parting shot, an opportunity to offer a personal and frank view of the host country, the manners and morals of its people, their institutions, the state of their cooking and their drains. But it was also a chance to let rip at the Foreign Office itself and to look back on a career spent in the service of a sometimes ungrateful nation.

They where normally quite blunt there is a great book collating some of the best https://www.amazon.co.uk/Parting-Shots-Matthew-Parris/dp/067...