Spending over 183 days in the UK in any tax year may trigger UK tax residency. It may have also simply arisen from conflating other immigration rules and policies, as well as general prudence on the part of visitors. There is, for example, a limit on the amount of time that can be spent in the UK on any one trip.

Under the 2026 UK immigration rules, there is no hard "180-day rule" like the Schengen Area's 90/180 rule, but a Standard Visitor is typically allowed to stay for up to 6 months (180 days) per visit. However, the critical caveat is that you must not be "living in the UK through frequent and successive visits." Border Force officers look at your travel history to ensure you are not spending more time in the UK than in your home country. If you spend 6 months in the UK, leave for a week, and try to return for another 6 months, you will likely be refused entry as you would be deemed a "de facto" resident. For 2026 travelers from non-visa national countries (like the US, Canada, or EU), the new UK ETA (Electronic Travel Authorisation) system tracks these stays digitally. While you can technically visit multiple times in a calendar year, staying more than 180 total days in a 12-month rolling period often triggers intense questioning regarding your ties to your home country and your source of funding for such an extended stay.