E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Pontius Pilates Body-Guard.
The 1st Foot Regiment, now called the Royal Scots, the oldest regiment in the service. When called Le Regiment de Douglas, and in the French service, they had a dispute with the Picardy regiment about the antiquity of their respective corps. The Picardy officers declared they were on duty on the night of the Crucifixion, when the colonel of the 1st Foot replied, If we had been on guard, we should not have slept at our posts.