regardinghk, firstly welcome to FT.

What you’re missing is that the limit is for goods that you intend to permanently import into the UK (or EU, given the UK is currently part of the customs union).

So if stopped you could in theory be asked to verify that you’re taking the goods out with you again, but in practice HMRC is so chronically understaffed (a) you won’t be because they have far higher priorities and (b) no-one is going to be silly enough to ask a tourist if they are intending to leave their camera or phone in the country when they leave, because the only reason to do so would be because they’ve sold it - and no-one would bother paying an airfare to do so because they’d be massively out of pocket.

If they did intend to sell something, then of course it would be a commercial import and subject to whatever the duty agreement was between the respective countries (or WTO rates). The US specifically asks for a declaration on carrying of commercial goods on its customs forms, but these days that’s very much the exception - most countries operate as the UK and Europe does.