FFS, I am glad that most of you posting are not in the military, 'cos frankly your ideas about preventing the loss of the islands with the current UK military capability are total pigs@&t.
500N
Then use a Helicopter as well to drop a boarding party on board.
totally risible, not many helicopters carried by HM submarines, and as for AA I'm afraid the days of 'crossing the line' or 'reading the riot act' are long gone, whether you like it or not.