In the 1960s, he was jailed for four years for a hand grenade attack on the home of a former business associate. Only last week, his former fiancee, 19-year-old Tanaka Sali, told how he grabbed her by the hair in a jealous rage and beat her with a slipper until it broke because he suspected she was dating another man.Despite Van Hoogstraten’s undoubted callousness, Mr Browne, for a long time one of his closest confidantes, confesses to having enjoyed his company. “I was his amanuensis most of the time, and towards the end I became more like the ?nence grise,” he said. “He lived in a lodge on the land where the palace was being built, and I was one of the few people who had close access to him.”I did like him. He had a tremendous sense of humour, although admittedly it was of the gallows kind.”Of all the myths that surround Van Hoogstraten, Mr Browne is most amused by talk of his vast wealth. The tycoon has often boasted of his £500m-plus fortune, but his architect puts it closer to £40m.

Neither was he greatly impressed by Van Hoogstraten’s fabled artistic collection. Though it is reputed to include one of a handful of Holbein paintings in private hands, Mr Browne only ever saw a Jasper Johns and a Turner oil sketch of a sunset scarcely bigger than a postcard.Moreover, he recalls Van Hoogstraten admitting on at least one occasion that he could not even remember which alias he had used to sequester certain assets, nor in which Swiss bank they now lay. He did, however, admire his antiques, notably a selection of French baroque pieces including a Louis XVI cabinet by Weisweiler, and his vast array of stamps and coins.Mr Browne disclosed that, in addition to the sprawling Hamilton Palace, he had designed a near-identical mansion for Van Hoogstraten’s estate in Zimbabwe. This too remains in a state of limbo.He also revealed that Van Hoogstraten had secretly ordered his henchmen to “liquidate” all his assets, including the three hotels and 60 townhouses he owns around Brighton and his luxury homes in Cannes, Monte Carlo and Florida, should his appeal against his conviction fail. “He always said that, if he got convicted, he would liquidate the lot,” he said. “He said people would just abuse it otherwise.”Of all Van Hoogstraten’s possessions, Mr Browne believes Hamilton Palace, with its blend of English baroque and Venetian styles and its half-built mausoleum, is the most fitting monument to his downfall.

“Its foundations are so deep, it would withstand a nuclear attack,” he said. “But it will never be completed now.”He added morbidly: “We’ve been joking in my office that they should convert it into a secure mental unit. That way, if he really does want to move in when he eventually comes out, he can.”Of Van Hoogstraten himself, with whom he parted company two years ago over a dispute about the tycoon’s increasing interference in his work, he concluded: “When he used to shout and bully people it was an act But it only used to be. Once you start acting insane, before too long you become insane.”. The families of five people killed in a fire at a flat linked to Nicholas van Hoogstraten have called on police to re-open the 10-year-old case. But relatives of the victims have always believed there was more to the incident, pointing to a fire investigation report that concluded it was the work of an arsonist.It has also been claimed that unemployed Mr Carrington, who was knocked down and killed by a truck shortly after the inquest, was in receipt of a large sum of money held in an offshore bank account.A few months before the fire, the leaseholders had won a legal battle for the right to buy the freehold, overturning an earlier sale between two companies alleged to have strong links with van Hoogstraten. His lawyers deny the jailed tycoon has any connection with the building.Van Hoogstraten gained a terrifying reputation for violence and intimidation as he built his property empire.