Nobody really needs to go to New Zealand unless they’re from there. London is an international hub for multiple industries. It’s much harder to prevent people from traveling there.

If this pandemic has taught us anything it's that hardly any of us need to go anywhere.

As modest as the NZ economy is it's still a hub for a few industries, and people still wanted to come for business purposes.

we never shut the airports (or the channel tunnel). If you arrived in the UK you were told to quarantine, but not made to.

Also our politicians are deeply incompetent and were the only ones in Europe (AFAIK) aiming for herd immunity right off the bat, until they eventually ran the numbers on death rates if the ICUs ran out of capacity and realised it was a terrible idea.

Right, so it's far more to do with institutions and policy than it is to do with how big an ocean you're in. NZ could have done the exact same thing - kept flights going, asked people politely to quarantine, etc.

Very true, but if you're a country with porous borders then it's going to be much harder to enforce. Border control is a prerequisite to enforcing transit quarantine, as well as having said rules in place, and border control is easier for an island.

Britain is so close to continental Europe that being an island is irrelevant. Also, it has a population of 66 million compared to NZ’s 5 on just as small an island.

1. New Zealand isn't "an island", there's two, one is slightly bigger and has less people.

2. Is your implication that the UK is so close to the mainland that the covid numbers are high due to people coming over in rafts? In that case the UK should have lower covid numbers because it has a much larger navy covering a the english channel, irish sea, and the north sea. Where as NZ has to cover the entire south pacific.

For #2, there are people crossing in boats https://www.bbc.com/news/uk-england-kent-58100694 (and I don't think there's enough will to use the Navy to stop them).

1. Sure, it's a figure of speech. And the number is way greater than two, if we're going to be nitpicky.

2. My point is that there's way more people entering, leaving, and going from A to B for whatever reason. Not trying to judge people, just stating a fact here.