The French government has taken billionaire Foxtons founder Jon Hunt to the High Court over his attempt to dig a so-called 'mega basement' in their grade II listed house next to the French embassy in central London.
Press reports suggest that Hunt and his wife Lois have started work on their home - the former Soviet mission next to the French embassy in Kensington Palace Gardens - with a view to a mega-basement accommodating a classic car collection.
The couple were first granted planning permission and listed building consent in 2008 with a smaller scheme receiving listed building consent in 2010; in 2011, freehold owners Crown Estates granted a limited licence to allow excavation to go ahead.
However, the French government is now challenging the validity of some of the consents granted by Kensington and Chelsea local authority and a court has heard allegations of a lack of appropriate consultation.
If the French government win its case, it could lead to the Hunts having to make fresh applications to finish the work, under the local authority's new and stricter guidelines government basement developments.