The other night, my friend Xan and I were round at Sarah's place, trying to figure out what was the best British post-war novel. That's the sort of thing that happens when a Guardian film writer, literary web editor and arts writer get together after hours over a bottle of red wine.

Seriously, we were: because, specifically, of the surprising puff by Philip Roth on the back of my copy of John Le Carré's novel A Perfect Spy (1986). "The best English novel since the war." OK, he says English, but let's broaden this to British for the sake of argument.

Well, I was the only one in the room who'd read A Perfect Spy. And, while I did spend a lot of time while reading it trying to convince anyone who'd listen how excellent it was and how Le Carré was criminally underrated as a literary novelist, I wasn't prepared to accept Roth's assessment. There are problems with A Perfect Spy, not least that there's a bit too much of it.

So what the hell is the best British novel since the war? It occurred to us that it seemed much easier to come up with great 20th century British novels written before the war. We hovered around Graham Greene for a bit (The End of the Affair) and thought, surely there's something later. We paused at Evelyn Waugh and we toyed with Iris Murdoch (The Sea, The Sea). We thought about A Clockwork Orange for a while. I made my usual and predictable case for Muriel Spark but couldn't quite convince myself (which of these slender, glistering novels would you choose anyway? The Prime of Miss Jean Brodie?). We started scanning Sarah's shelves in mild desperation. Byatt? Mantel? Amis got the thumbs-down and McEwan an emphatic shake of the head. Rushdie: well, yes, Midnight's Children and all, but none of us really loved the book. We began to think British fiction a feeble thing compared with American novels of the same period. This was depressing. Help us out?