THE Tube scares me. It's not the terrorists that terrify me or the mad people who may or may not stab, maim or push me on to the tracks at any moment.

It's not even the notion that a vicious, salivating half-man, half-beast might be just around the next bend to rip me limb from limb that puts my nerves on edge (okay, I admit it, I have seen An American Werewolf In London way too many times).

No, the thing that makes me quake with fear about the Tube - my heart is starting to pound at the mere thought of writing it down - is the idea that I might make a complete and utter buffoon of myself.

I admit it, the Tube baffles me. The map might look pretty but it makes about as much sense to me as a delirious Glaswegian talking Esperanto with a mouth full of marbles.

I have no idea where one zone ends and another begins. The mountainous escalators make me dizzy. I always lose my ticket. And everyone I ask for assistance always turns out to be a) as lost as me, b) foreign, c) a lovable, cheeky cockney sparrow who tells me to 'eff off' or d) a mad person looking for someone to stab, maim or push on to the tracks.

The Tube is one of the most soulless places on earth. It's dark and dirty. It's either freezing cold or bone-meltingly hot. The air feels like a thousand people have breathed it in and sneezed it out before you. And the atmosphere is less 'carnival in Rio' and more 'crematorium in Clapham'.

But there is no avoiding it. I can't afford a taxi and the buses are just as baffling and four times as slow. So if I want to go anywhere in London that isn't within walking distance of King's Cross, the only way to travel is the Tube.

Which is precisely where I found myself a few days ago. I had to be in Highgate by 2pm to do some filming for a forthcoming BBC2 series (yes, I am going to mention it every week and, yes, I will get over myself eventually).

The first two hours of the journey were a doddle. All I had to do was drink free coffee and read free papers on the train, while listening to an Italian woman complain on the phone, loudly and with a distinct Latinate over-emphasis, for 45 minutes about a pink dress that was supposed to be a size ten but didn't seem to fit (if she was a size ten, I'm Kate Moss's body double).

The next couple of hours, however, were less relaxing. I managed the mammoth journey from King's Cross to Euston - it's one stop, but who's counting - and then found myself at a complete standstill. Or rather the High Barnet train was at a complete standstill and I was jumping up and down with frustration.

After several minutes studying the screwed up Tube map in my pocket (it was upside down for at least half the time, but I didn't notice), I devised a cunning plan to jump on a train to Camden and catch another connection there. I thought this was incredibly clever, even devious, until I reached Camden and realised that every other living being in the city had had the same idea. Sardines are comfortable in their can compared to how we felt. They are merely snuggled together; we couldn't all breathe out at once for fear of a tunnel collapse.

I eventually made it to Highgate, nestled snuggly in the armpit of a man suffering a nose-bleed, only to find that I had bought the wrong day pass and couldn't get through the barrier without buying another.

Two hours later, I was back at the station and on my way home. Only this time I couldn't find the right platform. One kind soul pointed me in the wrong direction with her middle finger before a strange-smelling woman with a bald patch ushered me trackside.

Five stops later, I was back at King's Cross. But, once again, the barrier refused to open. The day pass I had bought at Highgate was not useable in this zone, whereas the day pass I had thrown away at Highgate was.

If the arid atmosphere of the Tube hadn't completely dried up my tear ducts, I would have cried. Instead I simply slumped against the wall and shared a moment of deep understanding with the loony slumped next to me (I believe he was a loony of the maiming variety).

Next time I'm going to take the bus.