Celebrity is a national drama whose characters' parts and plots are written by the tabloids, gossip columnists, websites and interactive buttons. The famous don't actually have to turn up to their own lives at all.

Get up now and go and find Robert Kilroy-Silk. Smile in a warm, friendly sort of way, then punch him on the nose. Now go and find Robert on television, despite my best endeavours, this is still relatively easy to do. Wait for a close-up, same smile, and punch him on the nose. If you followed the instructions carefully, you will have noticed a distinct difference. On the one hand, you were suffused with a sense of public-spirited righteousness; on the other, you're probably dribbling blood. That's the difference between reality in life and reality on television.

Making a programme that appears to condone a positive stereotype actually enforces all the negative ones as well. It says that they all have a valid point. To assert that Americans are naive, Germans humourless and the French arrogant is one thing: they're big enough to take it. But to say that there's a conspiracy of Jewish bankers, that gypsies are thieves, Pakistanis are dirty and refugees are muggers is something quite else.

A broadsheet obituarist once pointed out to me that veteran soldiers die by rank. First to go are the generals, admirals and air marshals, then the brigadiers, then a bit of a gap and the colonels and wing commanders and passed-over majors, then a steady trickle of captains and lieutenants. As they get older and rarer, so the soldiers are mythologised and grow ever more heroic, until finally drummer boys and under-age privates are venerated and laurelled with honours like ancient field marshals. There is something touching about that.

Is it a particularly British trait to so utterly adore truly appalling men, from Tony Hancock through to Steptoe and Alf Garnett, Captain Mainwaring, Rigsby, Del Boy, Victor Meldrew and on to David Brent from The Office. The most deeply adored characters are all simply vile.

You either get the point of Africa or you don't. What draws me back year after year is that it's like seeing the world with the lid off.

Celebrity is a national drama whose characters' parts and plots are written by the tabloids, gossip columnists, websites and interactive buttons. The famous don't actually have to turn up to their own lives at all.