I would just like to point out that the Russians are constantly invading UK airspace and testing UK capabilities.(At least once a week) I would say that it's a throwback to bygone times, but it's not, these incursions dropped right off after the end of the cold war but started again in the past few years.
Even if there is no tangible threat right now, there are people constantly watching and looking for weakness. Some of the incursions include nuclear capable bombers and UK tornados are regularly engaged in electronic warfare of one kind or another during these incursions.
They are constantly testing us and any drop in our capabilities is immediately clocked.
Just something that seemed pertinent.