Tim
We'll always need to protect our trade routes, I believe the RN still does a fair bit of fisheries protection, though some of it is done by the Scottish Fisheries Protection Agency. I think I'm right in saying that the last international British naval 'operations' before the Falklands were in the Cod War.
How long will it be until AQ learn the PIRA lesson that you can shoot as many Jocks & Toms as you like, the Western Powers only ever sit up and take note when you hit them in the pocket? For PIRA, it was shifting target from Belfast to The City. The offshore oilfields are vulnerable and our Fishhead brethren may correct me, but I'm sure they have significant operational plans in place to deal with threats to the platforms.