Nevertheless, he signed up as a writer for the series. Perhaps it was the fee — we were offering £750 a programme, remarkably high for those days, worth over £11,000 in today's money. Betjeman, an extremely generous man by nature, was always concerned about income, unsurprisingly for a life-long freelance with two houses, a wife, children, a lady-friend or two, and an expensive lifestyle to support. "I'm frightfully rich!" he would say, as he pulled out wads of notes to buy another round. As usual, in Betjemanese, this meant the exact opposite. He was always worried that one day, suddenly, fashion would change, his poems would be rejected, his contracts terminated, and he would finish up, as he would say, in the workhouse.

There weren't many workhouses by the late '60s, but I saw another famous writer with whom I worked, Sir Angus Wilson, fall into sudden and irretrievable penury, so it was not a wholly irrational fear. Betjeman always instructed his agent, bubbly Sue Freathy, to demand outrageously high fees, and he turned down proposals if he felt the BBC was underpaying him. Luckily, not in this instance.

Betjeman knew about films. He had been a film critic, contributed to books about films, performed as an actor in private films. There had been all those short films for Shell and others, and TV documentaries with Jonathan Stedall.

But in Bird's-Eye View his involvement was limited to the cutting-room. True, he suggested possible locations for filming, and was even persuaded, in North Cornwall, to venture once more into the air — "OOOH, it's just like getting drunk!" he screeched, as the pilot auto-rotated down towards a tiny island in the glistening sea.

But apart from that, the films were shot, assembled, edited and finished before he turned up. His job was the commentary. The cutting-room was in Soho, just off Wardour Street, in those days the centre of the British film industry. It was a small, friendly, slightly run-down sort of place, that John came to love. He observed Soho shops like the music publisher Peters Edition, and pretended that it was the home of Peter Sedition, an anarchist. Among the occupants of our building he spotted the name Ben Henry OBE, a person he never met, but speculated about obsessively. How was dear old Ben getting on, what services precisely had he performed to earn his OBE?

John would arrive at about mid-morning, and settle down in front of the Steenbeck, the film editing machine, running the sequences backwards and forwards, forwards and backwards, soaking in the rhythm of the editing, before setting pen to paper. He would write on A4 pads, tearing off sheet after sheet of unsatisfactory words, scrunching them up, and throwing them on the floor. (The editor and I would dive for them after he left.) His handwriting was not good, and got worse as time went by. Sometimes even he couldn't read his spidery scrawl.