In most cases settlement (Indefinite Leave to Remain under British law or Permanent Residence under European law) requires a period of “continuous residence” in the UK for a specified number of years. In many cases it is five years but it could be a different figure.
But what does “continuous residence” mean? Intuition might suggest that it does not take the literal meaning, ie that the migrant has to stay in the UK for 365 days per year. In this case intuition would be right: the various immigration rules do not insist on 100 per cent attendance to achieve continuous residence. It is, as it were, only reasonable that migrants can go outside the UK temporarily to go on holiday, visit family etc.
But where comes the limit? There have been various changes made to the relevant parts of the immigration rules in recent times and the general rule for working/investment visa holders (eg Tier 1, Tier 2 General, Representative of Overseas Business, Ancestry visa) is now that the migrant must not have been outside the UK for more than 180 days per 12 months to qualify for Indefinite Leave to Remain. Keen mathematicians will spot that this is slightly less than half the time, but nonetheless the rule seems quite generous. It allows, for example, a migrant to travel extensively outside the UK to carry out business, which for migrants in some situations is essential.
It is strongly worth noting that these requirements now also apply to dependants of Tier 1 and Tier 2 visa holders, not just to the working visa holder themselves; but, rather inconsistently, they do not apply to dependants of Representatives of Overseas Business or Ancestry visa holders (not at the time of writing, anyway!).
But there is a little trick here. The wording of the 180-day rule now goes like this: the migrant must “not have been absent from the UK for more than 180 days during any 12 month period in the continuous period”.
As we were often taught at law school, every word in a rule may be crucially important, and this is a good case in point. The crucial word here is “any”. The ramifications of this could in some circumstances be quite difficult, and again the keen mathematical mind may be required. If, for example, a migrant has an absence of 100 days in 2017 and another absence of 100 days in 2018 they may think that they have not offended the rule, but they might be wrong.
If the first absence occurred in late 2017 and the second absence occurred in early 2018 then the rule would have been offended, because both absences would have occurred in “any” 12-month period and there would have been total absences of 200 days.
The rule is therefore in some circumstances more onerous than it appears to be at first glance, but this is not the only problem. The rule changed in early 2018 but before that it was more liberal. Some migrants in some categories who were previously relying on the old, more liberal, rule may now find themselves in difficulties.
This subject has become a rather arcane aspect of the immigration rules, and if your situation is engaged by it then you would be well advised to consult a top-quality lawyer.
The same sort of rules apply to EEA nationals and their family members in regard to Permanent Residence. The relevant EEA Regulations refer in roughly similar style to absences which “do not exceed six months in total in any year”. However, the Regulations (unlike the British rules) do have a specifically-stated discretion for longer absences which were for an “important reason”.
But those on a spouse/civil partner/unmarried partner visa route under the British rules will be pleased to know that the rules for absences and Indefinite Leave to Remain are easy to understand, because effectively there aren’t any! There are no 180-day rules or anything similar; the only stated requirement is that the migrant must have been “in the UK” for the relevant period, which is surely very vague.