I graduated in the early 90s and worked in Holborn. Friday lunch sessions, a few hours at the desk and then back in the pub after work were routine. There was always someone having a midweek session afterwork if you wanted it as well. Brutal when I think about it. Being close to Soho meant there was always a risk of ending up in a dubious late night club as well.I'd like to put a word in for the 90s - the early 90s anyway.
At my first job, the local pub - The Golden Lion in Durrington - did a very brisk trade each lunchtime from workers employed at the nearby offices.