In all the furore over non-doms, attention has moved away from ‘residence’. But what makes you a tax resident in the UK in any given tax year?

Disputed cases on this issue continue to clog the courts. Despite some success in recent litigation, HM Revenue & Customs seem set to change the law, no longer discounting all days of arrival into and departure from the UK in the annual ‘day count’.

Instead they will look to where the individual is at midnight on each day. The argument is that the old rules were rooted in the days of the steamship, and the new approach reflects the greater speed of air travel. What’s wrong with that?

For a start, there is no single day count for determining UK tax residence. Under HMRC practice if you are in the UK for 183 days in a tax year, you are UK resident. But you can also be resident here if, for example, you are in the UK for an average of 92 days a year over a four year period.

If you have spent most of your time here in previous years, you will get to that ‘average’ figure in the current year however little time you spend here. So if you want to be non-resident, you have to have a change of lifestyle sufficient to count as ‘leaving the UK’ to re-start the clock. And what constitutes a change of lifestyle is a qualitative test.

As such all these practices are just that ­ rules of thumb, not of law. When cases come to court, the judges examine all the facts, so if your main home base is here, unless you can show you never set foot in the UK for a year, or you are working full-time abroad, you will still be classed as a UK resident.

Against such a confused background, fine-tuning which days of departure and arrival count becomes ridiculously overcomplicated.

This is madness. There needs to be a single, clear set of rules. Otherwise people who are determined to avoid UK tax residence will stay away for more than they need to ­ a pointless loss of business and pleasure that will increase compliance costs and pointless litigation.

Let’s do as most other countries do, and have a single, clear day-count ­ maybe based on a weighted average of the last few years ­ as the centre-piece of a new, comprehensive, statutory test of residence and present a more modern and welcoming face to the world.

John Cullinane is chairman of corporate tax sub-committee at the CIoT, and tax partner, Deloitte