HM Revenue and Customs (HMRC) have had yet more success in moving the goalposts - and back-dating the move.
This would play havoc in the football league.
It could play havoc with tax payers if the principal is adopted more widely.
Tax liabilities for past years, which are thought to be agreed and settled, may yet be recalculated because of a change in the accepted interpretation of some of the rules.
It is bad enough that HMRC can make 'discoveries' (of errors) to upset tax for earlier years, but their apparent ability to have a re-think and thereby change the basis of calculation some years in the future is a worrying trend.
There should and must be better certainty than that.
The present matter concerns a businessman, Robert Gaines-Cooper, who has been treated as non-resident (in the UK) for many years.
He has relied on spending no more than 91 days in the UK in any one year, which has been accepted, generally, as the test for residency for some time.
HMRC have recently disputed this basis and the courts (so far) have agreed and allowed them to back-date the ruling.
HMRC have successfully claimed that the tax-payer has not been non-resident because he had not cut his ties with the UK.
He retained a large estate in the UK and other aspects of his life indicated he remained resident and ordinarily resident despite abiding by the '91 day' rule.
It is too early to say what approach HMRC will take with this ruling and how they will try to apply it in other cases - but we must all be aware that HMRC's powers are changing and their ability to change the rules retrospectively is difficult, if not impossible, to guard against.
It is likely that these actions by HMRC are designed to stop people trying to manipulate tax rules with tax avoidance schemes in the knowledge that they are likely to be overturned retrospectively.
Schemes are often arranged in the certain knowledge that their life-span is limited.
The schemes will have little point if their life-span is nil as a result of back-dated legislation or interpretation.
I think I would applaud that - but whose judgement determines what is effective tax-planning and what is tax avoidance? And who gets caught next with an unexpected back-dated tax bill? (and lawsuit?).