It would have been deeply humiliating.”But Wilson enters on to all this reluctantly He is most anxious now to let his building speak for itself And so it does. The blank-walled exterior may look like an over-scaled version of a toy-town Tesco but it belies the grandeur of an interior which feels imposing without being intimidating.The entrance hall is welcoming and self-explanatory. “One hard moment was switching on the car radio and hearing the tail-end of an interview with David Mellor, who was saying, ‘The only thing wrong with the British Library is the architect.’ It was libellous and completely cynical on his part; but he knew I wouldn’t sue. Then there was William Waldegrave who began talking, when a lot of it was already built, of turning the place into a book store with a tunnel to the British Museum. That was the worst moment of all because going off at half-cock would have been worse than not doing it at all.

The idea was to bring greater control and flexibility; the reality was a chaotic nightmare of sub-standard work. The newspapers had a field day with lurid, and not always accurate, reports about 200 miles of moving bookshelves which juddered, 5,000 sprinkler heads which were found to be rusty, and 2,000 miles of electrical wiring which had to be ripped up and replaced.None of this was the architect’s fault but he seemed to bear the public opprobrium. The Tory government had failed to provide adequate management of the 150 sub-contractors. For ideological reasons ministers insisted that the project should follow a “construction management” costing policy – instead of fixing the price at the outset, the government insisted on agreeing payments to contractors as it went along. It launched an investigation which catalogued 230,000 construction defects.

The government was pretending to be realistic but pulling up the plant every 18 months to inspect its roots and see how it’s doing is the most expensive way to build.”Eventually the project drew the attention of the National Audit Office, the nation’s spending watchdog. We had to build things – like a secure reception area and a tunnel to deliver priceless manuscripts – which were going to be knocked down It was a waste of more than pounds 1m. I had to keep staff on the payroll – you can’t just chuck them out and then get them back in six months’ time It was so wasteful. There then followed at least five major shifts in the planning “It was stop-go for years It was simply appalling. We never knew with each bit of funding whether we’d get the money for the next bit, and so it went on.” During the waiting he kept busy working on the details, making more than 2,000 separate drawings and sketches for different parts of the library.”We tried to be pro-active and keep working on how we would approach the next stage if it were approved.

A bigger site was needed and one was found on the railway goods yard on the Euston Road to the west side of St Pancras Station where Wilson’s library now stands.When Shirley Williams approved the scheme for the last Labour government in 1978, the plan was a three-stage project. But a year later the Thatcher government began what was to prove a tortured process of cuts and changes The first phase was subdivided into three phases. In 1964, the two were commissioned for the project, which one civil servant told them with masterful understatement “may take quite a time to build”. Wilson, who had to his credit a number of university buildings, turned down the job as head of the architecture department at Yale to do the library.Today he does not regret the decision, though it was to bring him 30 years of grief. “I’ve always really wanted to commit myself to something really big. Next to a cathedral, which is to my mind the most transcendent of buildings, a library comes next; it is in its way also a sacred building.” But the first two schemes, on the museum’s Bloomsbury site, came to naught. “Sadly all my family are dead,” he says slowly, as if surprising himself with the thought, “and so are many of the friends I would have wanted to show it to.”The saga began in 1962 when it was decided to extend the British Museum’s library in the heart of Bloomsbury.

Then, in 1972, the Museum Library and the national Science Library were merged, by an act of parliament, to form the British Library. Wilson was then a lecturer in the school of architecture at Cambridge, and in private practice with the department’s professor, Sir Leslie Martin. So I carried on.” The unhappy thing is that it is not just his father who is not there to see his achievement. He did a lot of hanging in there – opposing the government over the Spanish Civil War, making a speech in the House of Lords on the atom bomb, which was received in deadly silence. My Dad also had a hard time [he was Bishop of Chelmsford and known then as the Bolshie Bishop]. A coalition of its present bookish users, former readers wistful for their romantic student days and traditionalists in love with the room’s historic associations with Marx, Freud, Dickens, Wilde, Shaw and other lustrous names, together created a storm of fury which was fierce and unabated.”It was very demoralising But then most of my blood is stubborn Scots.