A developer who built a luxury house disguised as a barn on greenbelt land has lost the final stage of his legal battle to live in his home.
Alan Beesley, and his wife Sarah, now face losing their house at North Brook Meadow near Potters Bar, Hertfordshire.
Last year the Court of Appeal ruled the couple could continue living there.
But now the Supreme Court has overturned the Appeal Court judgement, criticising Mr Beesley's "dishonest" conduct over the £500,000 home.
Mr Beesley was granted permission in 2001 to build a barn for agricultural use only, but fitted it out as a luxury house complete with three bedrooms - two with en suite bathrooms - a study, living room, a garage and gym.
Immunity from enforcement
From the outside, the property looks like any other hay barn with a curved roof, no windows and surrounded by farmyard machinery.
Mr Beesley, 38, and his 35-year-old wife Sarah moved into the completed property in 2002 and applied for a certificate of lawfulness four years later - by which time they believed the time limit of enforcement action had expired.
Welwyn Hatfield Borough Council refused but an inspector appointed by the Secretary of State for Communities and Local Government allowed Mr Beesley's appeal in 2008.
This was reversed at the High Court the following year.
Last year a panel of three appeal judges ruled immunity from enforcement had been established.
The council then appealed to the Supreme Court and now seven justices unanimously ruled in its favour, setting aside the certificate of lawfulness relating to the property.
The justices ruled that there had been no change of use within the section of the Town and Country Planning Act, which imposes a four-year time limit for taking enforcement action against breaches of planning control.
The court added that, in any event, Mr Beesley's "dishonest" conduct meant he could not rely on the section.
Lord Mance said Mr Beesley's conduct "although not identifiably criminal, consisted of positive deception in matters integral to the planning process".
Another Supreme Court judge Lord Brown pointed out that the council can "if it thinks it expedient, seek to enforce not merely against the continued use of this building as a dwelling house but additionally against its construction".
The council said it would now consider what "appropriate enforcement action" to take.