If you leave the UK and let your property here, your letting agent (or the tenant where there is no agent) should deduct basic rate (20%) tax from the rents paid after deduction of certain expenses, under the non-resident landlord scheme (NRL).
This ensures that at least some tax is paid on the income in the UK.
You can avoid having 20% tax deducted if you successfully apply for approval under the NRL scheme from HMRC. Approval will be granted where your UK tax affairs are up to date, or you don’t expect to be liable to pay UK tax in the year you apply.
The NRL scheme applies if the landlord’s usual place of abode is not in the UK.
This is not the same as being not resident in the UK for tax purposes. An absence from the UK for as little as six months can be enough to establish your usual place of abode as being outside the UK.
The NRL scheme applies to members of the armed forces and diplomats, just as it does to any other non-resident landlord. It also applies to overseas trusts and companies, which must have income tax (not corporation tax) deducted from their rental income.
If your UK property is let as holiday accommodation, you may need to register for VAT in the UK as holiday lets are subject to standard rate VAT. As an overseas person you have a zero turnover threshold for VAT registration, so you may have to register for VAT immediately on letting holiday accommodation. However, where a UK letting agent manages the property on your behalf, the VAT registration threshold of £79,000 applies for that landlord.