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Definition of 18 months in the Long Residence Rule

On 10 February 2021, the Upper Tribunal in the case of Mona Chang v Secretary of State for the Home Department [2021] UKUT 65 (IAC) made a judgement on what 18 months constituted in terms of total days for the 10-year Long Residence Rule (“Long Residence Rule”), when an individual is applying for indefinite leave to remain (“ILR”) – hitherto, with caveats it was generally accepted this meant 540 days.

The background in the case of Mona Chang was straightforward, Ms Chang had clocked up 543 days of absences during her relevant 10-year period when applying for ILR. The Home Office unsurprisingly rejected her application for ILR on the basis she had been absent from the United Kingdom for 3 more days over the permitted 540 days. The First tier Tribunal judge upheld the Home Office’s decision on the basis that their guidance defined 18 months as 540 days. Ms Chang then appealed the decision to the Upper Tribunal on the basis the judge had misdirected himself.

Judge Rintoul of the Upper Tribunal noted, no one disputed there was no definition of how many days there were in a month and with reference to earlier cases, stated:

“It is self-evident that not all calendar months are of the same length.”

He noted when granting, 6 months leave, the end can be ‘determined precisely – even though the exact number of days in that period will vary’ as the period is continuous. However, in the Long Residence Rule, the relevant 18-month period is calculated over shorter periods and hence there can be variations.

Judge Rintoul talked about how there can be variations in the number of days per year and cited the fact the length can be different depending on whether it fell between non-leap years or not which is best summarised:

“Any year has either 365 or 366 days. Similarly, any half-year has either 182.5 or 183 days. As leap-years cannot follow each other, then a year and a half is either 547.5, 548 or 548.5 days.”

Using an average, it would be 548 days.

Although the Home Office’s argument was any ambiguity should be resolved by the relevant guidance, Judge Rintoul relying on the cases of Adeyodin v Secretary of State for the Home Department [2010] EWCA Civ 3 and R (Alvi) v Secretary of State for the Home Department [2012] UKSC 33 pointed out the only way to ‘toughen’ up the rules is to lay them before Parliament and therefore any ambiguity should be in Ms Chang’s favour.

It is worth noting the Home Office guidance at time of writing still defines the 18 months as 540 days. It will be open to the Secretary of State to formally change the Long Residence Rule to define the 18 months as 540 days, but for the time being there is scope in the rare cases where individuals find themselves just over the 540 days but less than 548 days when applying for ILR through the Long Residence Rule to be successful.

One should note there may be extenuating reasons as to why an individual may exceed the 540 days for example due to ill-health or even COVID-19 and could still succeed in an application for ILR through the Long Residence Rule but this was not covered in the case of Mona Chang.

RLegal Immigration Solicitors can assist with application for ILR through the Long Residence Rule or on other immigration related issues. If you are interested in our services please contact us by emailing us at by completing our online form or telephoning us on +44 207 038 3980 and of our immigration lawyers will respond to you.

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