I first met Pat in New York when I was working on the New York Times in 1987. They wanted a famous writer to give a tour of Green-Wood Cemetery. I suggested her and she agreed, and we went on this weird little walking tour. After that we corresponded often, and she invited me to stay for the weekend. She was living in this beautiful, remote part of Switzerland, near Lugano, in a house she had largely designed herself. From the outside it was a low, white-winged building that looked a bit like the Pentagon, with no windows. Inside it was a magnificent space that appeared to be nothing but windows. I’m not sure how she managed to pull off the same trick in her house that she did in her work. Quite sensibly she had built a separate wing for guests, far far away from where she worked and lived. She was a lovely hostess, but her regular diet consisted of scotch, beer and cigarettes. There was an ominous-looking ham hock in a pot; I’m a vegetarian, so that wasn’t very promising. By the end of the weekend I was delirious because I was starving.

I had brought along my then-girlfriend, who was of white South African heritage, and Pat made some assumptions about her that weren’t true. Her first question was: “What do you think about this one man one vote thing then?” My reaction was the same as if I’d been with an elderly relative – you’re embarrassed and try to say: “Let’s not have that conversation again, Pat.” Like many Americans who choose to live in Switzerland, she complained a lot about taxation. That seems to have fostered certain other conservative views – racism, I suppose. She was in the vanguard of support for Palestinian rights, and this often teetered into outright antisemitism.

Pat refused to engage with me for six months after the visit, until finally I picked up the phone and called her. Apparently I had deeply offended her by not commenting on the paintings that were hanging on the walls, some of which she had done herself. I hadn’t said anything because I didn’t like them. You don’t expect people who are so convinced of their own standing to be so sensitive in other ways. What I learned from that was: always comment on the hostess’s accoutrements.

Pat didn’t suffer fools at all, but she was very funny, in the way only incredibly dark people can be. She was always looking for things that could turn her mind in a curious way. You can’t be even a reasonably good writer, let alone a great one, while holding on to your nihilism. She could be great in company, and she was generous with her time and advice, always asking to read what I wrote, which in my experience is quite rare.

People say: “Don’t meet your heroes”, but I was not disappointed. She was complex in exactly the way that real human beings are complex. She died in February 1995, on the night I was opening one of my plays in the UK – a play I’d dedicated to her. I felt as if there was some devilish angel perched on my shoulder. It was a friendship full of coincidences and synchronicities, and I treasure it.

Phyllis Nagy wrote the screenplay for Carol, out now