The great thing about having a boyfriend is that you don't need to go out on your own any more. The bad thing about having a boyfriend is that you never get to go out on your own any more. Last night, I felt the need to go out, all on my own, spend an evening in isolation. And that's just what I did, at the King William in Hampstead. Copy of the Guardian in hand, I took up position at the bar and made mental notes:

Young foreign chap asks barmaid, "Can I have a One Point Six Six Four, please?" "A what?" "Uh, One Point Six Six Four?" "I'm sorry, sir we don't... oh, you mean...?" Pours him a pint of Kronenbourg.

Pot-bellied fifty-something man scurries in. The bar staff spot him and immediately start pouring a pint of Fosters. He grabs it and wolfs it down in one, his hands trembling. Five seconds later he is gone. I spot him entering a restaurant twenty yards up the hill.

At the bar are two almost identical people. He is willowy and camp, she is cropped and butch, but they have the same face. "We're brother and sister, you know," he tells me. Yes, but which is which? "Where do I know you from? I recognise your face?" "That's quite likely," I reply, "Lord knows it's been around enough."

Twenty minutes after he first came in, the fifty-something man from the restaurant is back. Another pint of Fosters disappears down his neck in five seconds flat. He rushes back to the restaurant. "Ooh," says the young camp barman, "if I knew a younger man who could swallow like that, I'd be a very happy man!"

The group of regulars at the bar pore over the escort ads in QX. "Ooh, that would keep you warm at night." "I've had him; he's not THAT big."

Restaurant man pops back in, despatches another pint of Fosters in five seconds, runs back to the restaurant.

Three Young People come in. The barman asks for proof of age. One of them pulls out a photocopy of a passport. Barman refuses to serve him. "But I'm 22!"

The quiz starts. "The first round is just like Family Fortunes - you know how that works." Do I look like the kind of person who watches crap telly on a Saturday evening?

Annoying "joker" at the bar shouts out stupid answers; totally random, as though he is reaching into his head and pulling out the first thing he finds there. "Name a famous cigar smoker:" "Marilyn Monroe!" "Name something you might see in a desert:" "Carol Vorderman!"

Three teams finish on the same high score. I am one of them. After lengthy adjudication, another team is declared the winner. I have no idea why.

The second round is general knowledge, forty questions. Pretty easy questions. Young Oriental person next to me stares at me in amazement as I breeze through them. "What county are Milton Keynes and Aylesbury in?" Buckinghamshire. "Which of the seven dwarfs has the longest name?" Not Doc, Sleepy, Sneezy, Grumpy, Happy or the other one; must be Bashful.

I falter on the musicals round: "Which musical starred a lead character named Lina Lamont?" I have no idea - Sunset Boulevard? Wrong. I come a real cropper on the history round: "Who was elected prime minister in 1946?" Was Churchill re-elected? I don't know - I go for a name I vaguely remember: Anthony Eden. Very wrong.

I finish on 35 out of 40. The winning team - team, note, team - get 37.

Restaurant man comes back in, another pint, another five seconds, another dash back to the restaurant. I ask the barman, "who is he?" "He's the chef at that restaurant." Tip to Hampstead residents: don't eat at the place with the stripy awning, next to Waterstones.

Oriental person coos at me, "Wow, you're so clever." "Yeah, you know." "My name is Jeff." "You're from... let me see... the Philippines?" "Oh my god, how do you know that? You know the hospital at the top of the hill? I stay in the residence there." "You're a nurse? I mean, I suppose you could be a doctor, but, er..." "Do you want to come back with me?" "Oh, I don't think so."

I totter off down the hill, taking hundreds of blurred photographs of moonlit churchyards and graveyards and pavements and reflections and unidentified objects. I may be drunk, but I'm an arty drunk. I gash my shin on a gravestone. I stop at an all-night corner shop and buy two bags of crisps and a packet of fruit shortbread biscuits. I know this only because I find the wrappers in my bed the next morning.

And, yes, the gents' toilet does still smell like fish fingers.