To give them credit, my airline (and I think practically every airline) would back up myself and my crew if we requested the captain call ahead for the authorities or to consider diverting.
The Brits are big drinkers, it often forms part of their holiday and when 'most' people work so hard for their week or two away I'm certainly not going to judge them on it, most are great people. Indeed, most 'loud' groups are actually nice passengers you just have to keep them in check, get them to tow the line. Occasionally some passengers will complain and often try to pin the blame on the crew. The hardest thing is that tolerances amongst other passengers differs widely, the same goes for crew.
Generally, despite people's perceptions , the problem flights are these long haul sectors where people probably feel the effects more as the flight goes on. Anecdotally, some will tell you that it is also pretty prevalent in the premium cabins aswell.
However, you then get the odd passenger who is 'truly' disruptive and in my experience, this isn't always the Brits.