While you will always be classed as UK resident if you are in the country for 183 days or more during a tax year, avoiding the 183 day threshold, and even avoiding the 90 days / year averaged over 4 years threshold, is not enough to prove non-residence.
Particularly for a UK national leaving the UK, shedding UK tax residence can be complex as residence is not subject to a rigid definition in tax law (other than to say you are definitely resident of you spend 183+ days in the UK in a tax year), rather the concept has evolved over the years based on rulings by the courts.
HMRC state that considerations include the purpose and pattern of your presence in the UK and your connections to the UK “These might include the location of your family, your property, your work life and your social connections”, for example;
- Where are your main family ties? Do you have a spouse, civil partner, children or other family members you are close to? If you do, are they in the UK or abroad?
- Where is the location of your main social life and ties such as membership of clubs / societies, events that you regularly attend or host, any regular recreational engagement such as annual sporting seasons to which you returning each year.
- Do you have business ties include to the UK such as owning or being a director of a business based in the UK, or having employment, including self employment, in the UK? If you do, you need to consider the extent, frequency and nature of those employment duties in the UK; if they are regular they are a tie even if they are not taxed, for example because of a Double Tax Agreement.
- Do you have property ties to the UK such as a house or apartment that you own or lease? Property held primarily for investment can be a tie to the UK if it also provides you with accommodation when you are in the UK. In some circumstances, your tax planning may involve you choosing to use a hotel when in the UK; if your employment package includes a house or apartment provided for your use while you are in the UK, it is a tie to the UK.
- If the nature and degree of your ties to the UK show that it is usual for you to live in the UK, you are resident in the UK. It does not matter whether you live here for employment, leisure, or just because you like being in the UK.
- If you have previously been resident in the UK then to become not resident you must leave the UK, either by making a definite break or by taking up fulltime work abroad.