Hot air over an office block

It has been called a variety of names: London's "first pop-art skyscraper", the "world's most expensive dog kennel", and "the concrete symbol of everything that is rotten in our society". Centre Point Tower - the high rise office block which stands on the junction of Charing Cross Road and New Oxford Street - has always attracted more than its fair share of controversy. Yet it was 25 years ago this week that the saga of Centre Point entered its most dramatic phase.

At 5.30pm on 19 January 1974, two men approached the locked doors of the tower. They were dressed as security guards, but they were not employees of the firm policing the empty building: they were protesters linked to the squatter's rights movements. Once they had gained access to Centre Point, the men threw open the building to a crowd of demonstrators. Within minutes, 100 people had poured in and barricaded the doors against the police. The occupation of Centre Point marked the building's 10th anniversary, and was intended to highlight the "selfish profiteering" which was allowing it to stand empty while thousands of families in London were homeless.

The building had never been let, for its owner - the litigious and elusive property tycoon, Harry Hyams - had said that he intended to let it to a single tenant, and a suitable client had never been found. There were rumours that Hyams was deliberately keeping Centre Point empty to enhance its value - though when the allegation was repeated on television he sued for libel, and won. It was not the first dispute surrounding Centre Point - and it was not to be the last.

Even the circumstances of its birth were controversial: Hyams had gained permission from the Greater London Council to build his tower twice as high as the rules permitted in return for providing the land for a road- widening scheme which was never completed. At the time of its construction, the 385-foot tower was the second highest building in London. Yet Centre Point's early years were rarely trouble-free. In 1972, Camden Council attempted to requisition the 36 empty apartments in Centre Point House - the nine-storey block linked to the tower by a glazed bridge; the legal battle which ensued lasted for five years, and was resolved only in the House of Lords.

Later, Harold Wilson was so exasperated by the property developer's inability to let Centre Point that he threatened to nationalise it. But the demonstrators beat him to it: "We have occupied Centre Point because ... it insults the dignity and humanity of the homeless and exposes the hypocrisy of politicians who profess to care but refuse to act," they declared.

The occupation lasted for two days, and ended with a rally of several thousand people. Fights broke out: 18 people were arrested, and eight people - including seven policemen - were injured. In the subsequent months of 1974, one floor of the building was let, and in 1979, the Confederation of British Industry rented more than half of Centre Point's 180,000 square feet of office space. More than 15 years after its completion, the guard dogs and security men who patrolled Centre Point were replaced by paying tenants - the tower had finally begun to fulfil its purpose.

What is the likely future of one of the capital's most controversial buildings? The Sixties experiment in high-rise living is commonly assumed to have failed, yet Centre Point Tower is basking in unaccustomed respectability: the Richard Seifert-designed building was recently given Grade II listing status, and its owner - the property company, MEPC - predicts it will go from strength to strength. One thing is certain: the chances of it being occupied again on Tuesday are remote.