It’s a cold, rainy Friday evening. I scooter through town, clattering along bus lanes and over the pavement, nod a polite hello to my great-great grandfather’s sculpture Eros at Picadilly Circus, and arrive at a posh hotel, where a famous biographer and his husband greet me warmly in the lobby. I’ve known him for years — he employed my wife as a researcher for his great book on the monarchy — and we’ve been pals since.

My stomach lurches though when we approach the bar because I recognise the strange person who is lingering behind it. This person is Chinese in appearance and wears a long smock, has a smooth, feminine face and speaks in a very distinctive, husky, high-pitched voice. It is hard to tell if this is a man or a woman. I decide that he must be a man, but I am not completely certain. I recognise him because a couple of years ago I had dinner by myself with the Famous Biographer, and he served us. He was very cheeky. S/he raised his/her eyebrows mockingly at the Famous Biographer and then gave my face and body a once-over, and said, ‘Ooooooh, he’s not nearly as tall and handsome as the lovely man you had last night.’ The F.B. was embarrassed on my behalf, and fumed that this was a very rude comment. He’d had dinner with the son of a very, very, famous actor, now dead, the night before and disliked the implication.

Two years on, the F. B. said to me, ‘Call me old fashioned, but I like to know someone’s gender when I’m talking to them.’ Nevertheless, he steeled himself and asked for us to be shown to our table. The waiter disappeared — and didn’t return. Reddening in the face, the F.B. led us to our table anyway. Fortunately, we were served by a nice Lithuanian waiter for the rest of the night, and all went smoothly.

The F.B. told me about his new life with Danish husband, who is an assistant headteacher in Denmark. ‘I am so glad I am no longer living in the States. I think the country is simply barbaric now. That dreadful man Bush is trying to outlaw gay marriage, he’s dragged us into a terrible, pointless war, he’s stripping us of all our civil liberties. The U.S. is now a police state. It scares me. The only civilised place to live is on the Continent. Denmark was the first country to make same-sex marriage legal, and is giving full citizenship rights to me now. I love it there. We live in a lovely country house, surrounded by fields, we have lovely neighbours who are not prejudiced. It’s very different from L.A. and New York.’

As the evening progressed we returned to more cheering topics. The F.B. made his name with the seminal biography of the greatest film director who ever lived, Alfred Hitchcock. My conversations with him always return to two films: Vertigo and North By Northwest. The F.B. must be the world’s greatest authority on these two films: he knows the scripts off by heart, and can recall in minute detail exactly how they came to be made. More that though, he is brilliant at analysing why they are such fantastic works of art. He always offers a fresh insight into them. ‘The triumvirate of Psycho, Vertigo and North by Northwest are all about people who do not exist. Norman Bates’ mother in Psycho, the fictitious George Kaplan in North by Northwest, and Madaleine in Vertigo are not real people. They are ciphers which allow other people to project their own wishes and desires onto them.’

As I was leaving I saw the waiter sitting in a pool of shadow by the bar. He looked sad and lonely. I sensed he needed to be rude to keep going on. Hitchcock had his films, the waiter had his cheek.