We have none at all.
At least twice in the last 20 years, it's been considered, but given our scale, the decision has always been that we're better off to maintain one highly capable maritime enforcement capability in the navy. Personally, that's a decision I'm very comfortable with. Therefore, the navy does perform a large part of our coast guard functions. It is actually the training ground for junior naval officers before they move into more capable vessels.
The one footnote to that is that our customs area does maintain a small maritime capability, now called Border Force. That's taking on a range of civil policing roles directed against drug movement and illegal people movements, the things that are well short of the serious conflicts that navies deal with.