Who would live in a £70 million house like this? Well, David, let’s go through the CCTV-monitored keyhole and marvel at 50,000 sq ft of Surrey real estate: 250 tons of Italian marble, 27 bathrooms, a quarter of a mile of under-driveway heating, 58 acres of landscaped gardens, an underground squash court, a bowling alley, a panic room with its own ancillary air conditioning and two indoor swimming pools – both filled with green stagnant water and beginning to smell.

The answer, it seems, is that no one lives in a house like this, and nor does anyone want to. Updown Court, five miles south of Ascot, was placed on the market in 2005, then the most expensive property in Britain. Six years – and numerous viewings – later, it has still not been sold. In a bizarre development at the weekend, it was reported that it is on the verge of being seized on behalf of the Irish taxpayers.

It would not be the first twist in the property’s colourful history. Bought by Prince Sami Gayed of Egypt in 1977, Updown Court was abandoned after fire damage following the storm of 1987. It stood empty for years before Anthony Pearce, a local engineer, acquired the site and tried to turn it into an Arab palace.

In 2001 40-plus Customs officials descended on the house, arrested Pearce and charged him with money laundering. Charges were dropped after an 18-month trial, but Pearce emigrated in a huff to North Carolina and Leslie Allen-Vercoe, a Middlesex-born property tycoon who made his money in Russia in the early 1990s, bought a half-finished shell for £20 million.

Turning to the roaring Celtic Tiger for further financing, Allen-Vercoe took out loans from the Irish Nationwide Building Society which eventually amounted to more than £60 million. Together they entered into an arrangement whereby his company, Updown Court, would develop the property. On finding a vendor, he’d pay back the loan and the rolled-up interest and split the profit 66:33 with the building 

Unfortunately, Irish Nationwide went bust, and was subsumed by the even more bust Anglo Irish Bank. A significant proportion of Updown Court’s debt (Allen-Vercoe estimates 50 per cent) is now owned by the National Asset Management Agency (Nama), Ireland’s “bad bank” operated on behalf of the taxpayer. Nama wants its money back, and is reportedly preparing to appoint receivers in the next few days. Yesterday it told The Daily Telegraph that it would not comment on individual loans or debtors.

Allen-Vercoe strongly denies knowledge of any receivership action and points out that, if receivers were to take over his company, the property would have to be sold independently, losing substantial tax and anonymity advantages to any purchaser. Although immune from major losses himself, he is unlikely to make any profit out of eight years’ unpaid work. “With the benefit of hindsight, I would have run a million miles,” he says, softly spoken and dapper in a pin-striped suit.