In a ruling which will be greeted with joy by the growing community of self-builders, a couple who made a very handsome return on their 'Grand Designs'-style project have been relieved of a six-figure Capital Gains Tax (CGT) bill.

The couple bought a plot of land for £1,679,000 before demolishing the house that stood on it and replacing it with a new residence. The project lasted for the best part of three years and, following completion, the couple lived in their new home for about 14 months before they sold the property for £5,995,000.

There was no dispute that the new home was their principal private residence (PPR) and that they were therefore entitled to relief from CGT. HM Revenue and Customs (HMRC), however, decided that they were entitled to only partial relief and that they had made a chargeable gain of £541,821. The couple appealed against that conclusion to the First-tier Tribunal (FTT).

The case hinged on the meaning of the phrase 'period of ownership' – as used in the relevant provisions of the Taxation of Chargeable Gains Act 1992 – where a house that is sold has been lived in since completion, but the land on which it is built has been owned for considerably longer than the existence of the house.

HMRC took the view that the couple's period of ownership began on the day they bought the land and that PPR relief was therefore only available in respect of the shorter period after the new house was complete. The couple argued that the period of ownership began when the house was signed off as finished. They had thereafter lived in the house for all but four days prior to its sale.

Upholding the couple's appeal, the FTT found that the period of ownership referred to in the legislation related to the new house, rather than the land. It noted that, prior to completion of the building works, there was no house in existence that the couple could have occupied as their PPR. Their interpretation of the statutory provisions accorded both with their natural meaning and their purpose: to enable the proceeds of sale of a residence to be invested in a new residence.