If you're moving to the UK and planning to bring say €100,000 in of your personal wealth while using the remittance basis, whether or not you'll have to pay tax on that money really depends on where it comes from.
If the money is from savings, income, or assets you earned before you became a UK resident, in other words, what’s called “clean capital” then you can bring it into the UK without paying any tax on it. The key is that it needs to have been earned before you moved, and ideally, you should be able to show some documentation that proves where the︀ money came from, just in case HMRC ever asks.
However, if the money comes from︁ income or capital gains that you earned after becoming a UK resident, for example, from︂ running a business abroad or selling investments, then bringing that money into the UK would︃ trigger tax. That income would be taxed as regular income, and gains would be taxed︄ as capital gains.
One thing to be careful about is if the money is coming︅ from a bank account that mixes clean capital with post-residency income or gains. In that︆ case, HMRC tends to assume that the taxable money is the first to come in,︇ so you could end up being taxed even if part of it was originally clean.︈
That’s why it’s really important to keep clean capital in a separate account and only︉ use that account for transfers into the UK.