This week flying with SWMBO East this week I decided to drink on the flight ( I don't usually). Several G&T's later, a mixture of seat service and fetch our own from galley.
For reasons that will be clear, I won't mention the exact flight, but in the end, one of the crew members simply plonked a full bottle of champagne on my table and with a wink said "enjoy".
So I did. I never did find out if they ran out of Tanqueray.....