A key feature of the Revenue's old guidance on whether someone was resident in the UK for tax purposes - known as IR20 - was whether they spent, on average, fewer than 91 days here each year.
"If you read the old guidance at face value, as most of us did, and you spent less than 91 days here, you would have been treated as a tax exile," said Mike Warburton of accountants Grant Thornton, who was an expert witness in the case.
However, the three Appeal Court judges ruled that it had always been the case that any would-be tax exile, first had to show they had really left the country.
Any continuing connections would mean that he had not actually cut his ties with the UK and would thus not be able to avoid UK taxes.
The 91-day rule, they said, did not in fact establish non-residency, and was "important only to establish whether non-resident status, once acquired, has been lost".
Source: http://news.bbc.co.uk/1/hi/business/8519803.stm