Alcohol has so much to answer for, so why is it that it’s always the people who drink it who get the blame ?
If you are having a Christmas staff party, it would be wise to remind people attending that tribunals regard parties as an extension of work. In other words, you must remain fully in control of your behaviour.
You might want to do this in writing so that no one can say they were not told.
Some employers arrange transport for the office party, but this depends on the size & resources of the employer