A recent case hinged on just a single day. The challenge, however, is that not every day is counted in the way you might expect.

So, what is a day?

It sounds like a simple question. Surely a day is just a day?

However, when it comes to determining your UK tax residence position, the answer is not quite so straightforward. Understanding what counts as a "day" in the UK can have a significant impact on whether you are a UK tax resident or non-UK resident for a tax year.

Your UK residence position is determined under the Statutory Residence Test. While this test considers a number of different factors, one of the most important is the number of days you spend in the UK during a tax year.

In some cases, the difference of just a few days can determine whether you are taxable in the UK on your worldwide income and gains or only on your UK-source income and gains.

A typical business trip

Imagine you are a non-UK resident business owner.

You land at London City Airport at 7:30am on Tuesday morning, pass through passport control, and head into the city for a 9:00am board meeting.

The meeting goes exceptionally well. Business is booming, everyone is happy, and by 11:00am you are finished for the day. You spend some time catching up with friends over lunch before opening your laptop in a coffee shop and dealing with emails, client calls and a couple of outstanding transactions.

By early evening, you make your way back to the airport and board your flight home, departing at 8:00pm.

No delays. No cancelled trains. A surprisingly smooth day in London.

Does this count as a UK day?

Short answer: No!

Slightly longer answer: For most purposes under the Statutory Residence Test, a day counts as a UK day if you are present in the UK at midnight. As you left the UK before midnight, this is not a UK day for the purposes of counting your days of presence in the UK.

Does this count as a UK workday?

Short answer: Yes!

Slightly longer answer: A UK workday is generally a day on which you perform more than three hours of work in the UK. Between your board meeting, emails, phone calls and other business activities, you have clearly exceeded this three-hour threshold. As a result, this day is a UK workday, even though it is not a UK day for the midnight test. This distinction is often overlooked but can be extremely important when assessing your residence.

Why Does This Matter?

The Statutory Residence Test uses different measures in different circumstances. Some provisions focus on the number of UK days, while others take account of UK workdays.

As a result, it is entirely possible to have:

• A day that is not a UK day but is a UK workday
• A day that is a UK day but involves little or no work
• Days that may be ignored for one purpose but remain relevant for another

There are also special rules that can apply in situations such as travel through the UK, exceptional circumstances and certain ties to the UK. The details really matter.

Keep good records

For anyone spending time in and out of the UK, maintaining accurate records is essential.

A detailed diary showing arrival and departure dates and times, travel itineraries, the location of overnight stays, and any work undertaken while in the UK, can be invaluable when planning your tax affairs and demonstrating your residence position if HMRC ever raise any questions.

When it comes to the Statutory Residence Test, knowing exactly what constitutes a "day" can make all the difference.

If you are living overseas, regularly travelling to the UK, or considering a move, please get in touch for an initial discussion about your residence position.