Like Boddingtons, Websters is a once famous and widespread brand that has died a slow death and vanished from memory once its home brewery closed. Grand Metropolitan sold the place to Courage around the time this ad was out, and soon after they were bought out by Scottish & Newcastle. Already having John Smith's in the portfolio (at the time outselling Websters by 300%), S&N saw no need for Websters to exist and shut the brewery in 1996 with the loss of 400 jobs. If any of those newly made redundant workers had somehow seen this ad then, it would have left a taste more bitter than any pint of Pennine ale.
Apparently, you can still find Websters in Yorkshire somewhere. The keg bitter is still being brewed by everyone's favourite contractors, Burtonwood. You will not see it advertised or promoted anywhere.
Talking horses and Yorkshire fast bowlers having better things to do, it seems.