“He’s got a big beard …” ponders site foreman Tom

The punter at the bar does indeed have some impressive facial hair but I don’t think he’s our man. Maybe I should explain. We’re in the Plumbers Arms where on the night of the 7 November 1974 that the bloodstained wife of Lord Lucan burst into the bar, crying “Help me, help me. I’ve just escaped from being murdered. He’s in the house. He’s murdered the nanny!”

It’s the sort of to-do that would spice up a Building Buys a Pint nicely but alas we instead make do with some wild speculation on the moustachioed lord’s whereabouts. South America? Africa? Canada? Well, nobody from the London Basement Company has seen him round here, and they’ve been inside more Belgravia homes than most.

Robin lays the blame squarely at his wife’s door. He was, he says, in the middle of divorcing her

“I’ve got a map on the office wall and we’re gradually colouring it in with all of the properties we’ve converted,” says Mike Wiseman, the firm’s design director. “Soon it will be completely red.” These are the sort of clients who, rather than move, extend downwards. It’s amazing what they can squeeze in below ground – swimming pools, saunas, cinemas even a self-contained flat for the offspring. And in the downturn, work is booming. “They’re generally not the sort of people who have to go out and get a mortgage,” says managing director Robin.

But I’m curious: how do you get into the business of converting basements for the rich and famous? Robin lays the blame squarely at his wife’s door. He was, he says, in the middle of divorcing her. As part of the settlement he bought her a flat and when she complained it was too small he offered to create a basement; this was not surprising seeing as he was, in the trade of waterproofing basements. To cut a long story short, they cancelled the divorce but they did sell the flat for a fat profit and a business was born.

‘We’ve just uncovered a Victorian sewer,’ says Tom, ‘in a property down the road. Fortunately it wasn’t in use’

So does this mean they all have swanky basements in their homes? Mike’s says his wife is dead keen on one. The problem is, he lives in Berkshire, where the ground is all chalk – there’s no way you could build one, he says. I take him at his word although it didn’t stop him digging a pit in his garage so he could service his classic car. “The problem is I struck a well,” he says. This is one of the occupational hazards of digging big holes. “We’ve just uncovered a Victorian sewer,” says Tom, “down the road. Fortunately it wasn’t in use.”

But I appreciate Tom’s analogy that the work is a lot like keyhole surgery. The only way to dig these basements is by hand. You then need to squeeze the materials in through a gap not much bigger than a doorway. “It’s like building a ship in a bottle”.

By our fourth round, it’s looking unlikely that the events of 35 years ago are going to be topped and so we decide to call it a night.

Venue: The Plumbers Arms, Belgravia
Ambience: Traditional one-bar pub, popular with after-work drinkers
Topics of conversation: Lord Lucan, wives and basements
Drinks drunk: 9 pints Bombardier, 3 pints Guinness, 8 pints lager, 2 Cokes

Robin Knowles managing director
Mike Wiseman design director
Grant Egmore-Smith surveying director
Tom Flynn site foreman
Stephen Kennett Building