Banking tycoon Sir Victor Blank has been ordered to pay Hampstead Garden Suburb Trust almost £65,000 after losing a High Court bid to stop an underground swimming pool being built near his house.

Sir Victor, 70, tried to obtain a High Court injunction to stop the trust from approving plans for a basement extension to a six-bedroom mansion near his Suburb home.

In April, judge Mr Justice Henderson found there were “no grounds” to stop the trust deciding on the application, by Scott and Melissa Franklin, to build a swimming pool, games room and wine cellar under their home.

The judge has since ordered Sir Victor to pay the legal bill - totalling £64,998 - accrued by the trust in contesting the High Court case, a debt Sir Victor says he has already settled.

Sir Victor originally launched the legal action against the trust in December in light of objections from a group of about 12 residents – including top judge Lord Justice Leveson and TV presenter Richard Madeley – who live close to the proposed basement extension.

The group fear that removing earth to create the basement could cause significant damage to neighbouring homes.

They are calling for the trust, which rules on every development in the conservation area along with Barnet Council, to explore the potential impact of the plans on underground water levels in the area and how this may affect houses near the luxury home.

Sir Victor had claimed the trust would be breaching his right to “quiet enjoyment” of his home by approving the excavation.

There is now the possibility of an appeal from Sir Victor against the High Court decision.