The 90-Day Tax Rule UK: When Days in the UK Make You Resident
There is no single 90-day rule. Under the Statutory Residence Test, your day count plus your UK ties decide residency. Fewer than 16 days can make you automatically non-resident; 183 or more makes you automatically resident. The 90-day tie applies if you spent over 90 days in the UK in either of the previous 2 tax years.
Fewer than 16 days - Automatically non-resident if you were UK resident in any of the previous 3...
Fewer than 46 days - Automatically non-resident if you were not UK resident in any of the previous...
16 to 45 days - Resident only if you have at least 4 UK ties (for someone resident in any of the...
46 to 90 days - Resident if you have at least 3 UK ties (previously resident) or all 4 ties (not...
Plus 4 more in the full guide
freedomisntfree.co.uk/guides/90-day-tax-rule-hmrc