We are not a world power
We are not a world any more. We haven't been for a very long time, so we should stop acting like one.
The navy, when supposedly engaged in anti-piracy measures (let's say off the coast of Somalia) is not even sure what authority it has to do so. The Foreign Office told the navy not to detain pirates, because it might breach their human rights! And it can't send the pirates back to Somalia because that might breach their human rights too! Furthermore, the Foreign Office said it is important to resolve things peacefully, so there really is no point at all in having the navy there. So what exactly is the navy doing there, apart from getting some wonderful sun tans at our expense? I'll tell you - it's pretending that we are still a great sea power with a global reach. But it is only "pretending", it's not the truth.
The North Korea thing - there is currently NO power from the UN to incercept North Korean shipping. The most that can be done is to ask nicely for permission to board, but boarding by force would be an act of piracy. If the captain of the North Korean ship refuses his ship to be boarded, his ship must be directed to a port that Pyongyang chooses (most likely a home port). North Korea is in no position to attack us. That's just a rehash of the 45 minutes load of crap about Iraq. So, again, if the navy is near North Korea, it's working on sun tans and not a lot else. Once again, a bit of pretend grandstanding, but no real teeth.
Our merchant fleet has about half a dozen rubber dinghies to its name. So protecting "British" shipping is a bit of a half-truth.
The navy is so small that it is all but useless. The loss of one ship would have a major impact on fighting capacity. We no doubt have more admirals than ships.
We don't have an empire to defend. And even offering help to friendly countries (let's say Australia was attacked by somebody unknown), what could we do? Offer a couple of ships at most. We are only a member of the UN Security Council for historical reasons, and that history is a long time ago now. "You are only as good as your last sale (or sail)...".
The political classes (at least the major parties) threw our lot in with the Americans a long time ago (without asking us, the people, naturally). We have become nothing more than America's stooge. We are a useful extra vote on the Security Council (to frustrate those cheese-eating surrender-monkeys, and to spite the Russians). We have some bases for America to treat as though it owns, and that is exaclt how America does treat them.
We should stop this pretence. And part of stopping it will be to ger rid of the navy. It costs a load of money and doesn't serve a useful purpose (any more).