ROBIN Ellis, the man acclaimed as London's poshest builder with a client list that included City tycoons and pop stars, was a spectacular casualty of the recession, it seemed. His firm went into administration just before Christmas, only months after he appeared in the Rich List with personal wealth estimated at £40 million. "We suffered a strangulation of cash flow," he said at the time, blaming the banking crisis for a sudden fall in orders.

But is that the whole story? The Evening Standard has been told a different version, one that Ellis may not wish to see publicly aired. It acknowledges difficult trading conditions but there are also allegations over the way that Ellis ran his business. A number of sub-contractors and clients told the Standard that Ellis did not pay his workers, although he himself had received payments for the work they did. His creditors are believed to be owed around £1.5 million. Most are sub-contractors, small firms and individuals whose annual turnover is less than £2 million.

Some people who worked closely with him during the heady years of the property boom - when he was said to be reluctant to take on anything worth less than £1 million - blame him for what went wrong. "He was heading for problems, even before the crash," one said. "Jobs turned into a fiasco."

According to a well-placed source, Ellis badly underestimated a major refurbishment of a house in Holland Park. After more than two years' work, it was alleged, he faced a loss of £1 million, tipping his company towards collapse and making 35 employees redundant.

The house, owned by a wealthy property developer, was a typical Robin Ellis project. The work involved gutting the building and installing a swimming pool. Swimming pools, often dug into basements, were Ellis's speciality. One client had one built so it could be covered over and turned into a 120-seat concert hall. That cost millions, it was reported.

But at the height of the property boom, money was not a problem. Ellis said in 2006: "London is so awash with money now. I can only compare it to 15th-century Venice for opulence and wealth."

A lot of this wealth came his way. David Bowie, Peter Gabriel and Vanessa Mae were among his clients. They joined a long list of City figures, bankers and hedge fund managers who queued for his services. Last year, a regular client was told Ellis could not fit her into his schedule until 2010.

Ellis, 54, is unusual among builders in that he has a background in architecture and design and could realise some of his clients' most extravagant desires. He was brought up in a modest semi in Bristol where the style included net curtains. He went on to study architecture in Liverpool and then designed kitchens for the upscale Smallbone group.

After starting his company in 1984, he quickly found that wealthy clients were anxious to indulge their whims. Retractable glass roofs, swimming pools and disappearing car bays with lifts were his stock-in-trade. He often dug 15 metres below a house to create space, a move that required supporting the house on steel pillars. One project included installing a passenger lift that stopped at the floor containing the owner's art collection only when his thumbprint was pressed on the controls.

A businessman and his heiress wife wanted a large, deep swimming pool but worried about the safety of their young children. Ellis devised a solution that was straight out of Thunderbirds: he built the pool with an adjustable floor. At the flick of a switch it could be raised to paddling pool depth. In the Klondike-style property rush of just a year or so ago, these and other schemes created a mythology around Ellis's name. He was supposed to have redesigned a Kensington house so that its owner could climb out of bed straight into a chute that delivered her to the swimming pool in the basement.

The story, repeated at dinner parties across London, has been published many times. It is, he insists, quite untrue. Intriguingly, the Standard has found an email Ellis sent detailing possibilities for exotic projects. His offers included: "Exercise pool (swimming against a current) ideally accessed by a gently sloping secret slide from the principal bedroom (what a way to wake up!)." He also suggested in the email subterranean wine cellars and a squash court and a "green roof, planted with sedum, camomile or corsican mint (the former is more durable but less fragrant than the latter)".

Ellis's reputation was such that he was believed capable of almost any wizardry. The standard of his company's work was legendary. Finishes were completed to perfection, a tribute to the skills of the many sub-contractors he used. Today, those craftspeople are among Ellis's fiercest critics.

Jim Quaid, a carpenter, says he was owed more than £50,000 when Ellis's companies, Robin Ellis Construction Services and Robin Ellis Projects, went into administration. Mr Quaid told the Standard: "He's just got fed up with his train set and thrown it out of the door. He would never answer the phone, it was so rude. He treated you as if you were lucky to be working for him. But if you walked off the site, you know he would go for you for breach of contract. For the last three years he's been the hardest person to get money out of."

Tony Cork, who runs his own electrical engineering concern, said he is owed £43,000, a significant sum in the scale of his company's operations.

"Jobs turned into a fiasco," Mr Cork said. "I sent him seven letters just before he went under. Some of the debts are so old they go back two or three years. He constantly gave us reassurances that although there were cash-flow problems things would work out. He'd say: 'Bear with us, everything will be OK.' The other directors seemed to be powerless.

"Over the last year we had five of his projects on the go. We were lucky to get paid on two. We got stung on three. When it all started to go sour we could only deal with subordinates. You were always kept a tier away from him.

You can't function as a small business when you are owed so much money," continued Mr Cork. "You always pay your blokes first, you delay your payments to the Inland Revenue, you pay yourself last. Last year I was so strapped I had to take an overdraft out with my house as security. It is quite demoralising, I feel like a fool, to be honest."

He thought Ellis had added insult to injury by asking sub-contractors to sponsor him in a charity bike marathon: "At the time he owed us all money."

Ian Allison, a partner in a painting and decorating firm, worked on the Holland Park house on which Ellis is believed to have lost £1 million. He said: "This guy has caused a lot of grief. They estimated the Holland Park job at £1.5 million and it came in at around £2.5 million. It's taken two-and-a-half years and they've only just finished it. It was a total refurbishment, he gutted the house, dug out the garden and put a swimming pool in there."

One of Ellis's clients described his own experiences to the Standard. The client, who asked not be named, said he had employed Ellis's firm to work on a project in west London.

"Fortunately my building was substantially completed before Ellis went into administration," he said. "But I came to learn about things that I find appalling. There were a number of sub-contractors involved and I've been on good terms with all of them. On our job there were circumstances where we paid for the subbies in full but it seems the money didn't get to them.

"Our project was about a £2 million job. Fortunately for us he was on the very last lap of the job before he folded the company. But he left a trail of unpaid people. The cash-flow problems were not obvious. We only learned about it because we were in touch with the sub-contractors.

"For example, the air conditioning contractor and the joining contractor only got paid by walking off the job. No one ever got paid all their money; it was just drip-fed. I feel aggrieved. I have a great deal of sympathy for the people who got caught.

"The quality of the work we always found excellent and when they started the job one-and-a-half years ago there were no indications of cash-flow problems. We employed them based on the reputation he had from other jobs."

Another client, whose London house was refurbished, said: "I was paying Ellis money which did not get to the sub-contractors who were doing the work. I feel terrible about it because some of those people are out a lot of money. I have had to bring back people and employ them myself to do stuff I had already paid Ellis for. In some cases I had to get new people because there was so much bitterness over the way Ellis behaved. It has cost me an extra £70,000 and, frankly, I think the way things were handled by him was deplorable."

After his companies' collapse, Ellis said they fell victim to a lack of confidence. "It's not that London hasn't still got a very large number of wealthy residents," he said. "It's just that people were minded to spend money on their property when they thought it would enhance its value. Now they are not so sure.

"Two years ago it was frankly ridiculous the way in which property prices were going up and the way in which people were trying to outspend each other. It was somewhere around the time of the Lehman collapse when projects were put on hold. Unfortunately, our top-end market was particularly focused on the financial sector, American and European bankers."

Ellis is still running three small businesses, a plastering firm, a property maintenance company and a design service. They are unaffected by the demise of his two building firms. He lives in Camden and runs his office from Fitzroy Road, Primrose Hill, where he has a large builder's yard. The land, valued at £2 million, is owned by Ellis personally, according to Land Registry documents, but a number of his creditors are asking whether it had previously been an asset of the companies that owe them money.

The administrator, Glyn Mummery, at Vantis Business Recovery Services, said the history of the land at Fitzroy Road would be investigated as part of the administration process. If the inquiries show the property cannot be considered an asset of the failed companies, it is likely that Robin Ellis's creditors will see very little of their money.

We made several attempts to discuss these issues with Ellis but there was no response from him.

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