Aware that he might have kept Judy in ignorance, I do not bring up Richard's Znargian origins. But, it turns out, she knows. 'He's extraterrestrial, he comes from another planet,' she says after some typically surreal Madeleyan self-analysis is interrupted by his mobile phone. It emits an ear-bleedingly loud polyphonic version of the Nokia ring tone.

'DA-DALA-DA, DADALA-DA, DADALA-DA, DA!'

'Factory setting,' he explains apologetically. 'It came like that.'

But never mind about alien origins, Richard and Judy are as British as fish and chips and asylum seekers. A whimsically daft but also extravagantly normal married couple, they present daytime-TV shows in a style that defies analysis. He improvises madly, apparently concerned that the world is not quite weird enough; she rolls her eyes and tries to subdue with common sense both her husband and the passing parade of celebs, experts, dingbats and bozos that roll through their studio. They talk over each other, bicker mildly and, lovingly, touch and gaze at each other.

Sweet, you might think, and happy, but the wholesomeness is repeatedly subverted by Richard's Znargian blurts. They were once asked what three things they would rescue if their house was on fire.

Judy: 'Jack and Chloe [their children]. I don't care about anything else.'

Richard: 'I would think, 'Let it burn. Let the fire cleanse me.'

See what I mean? Or, a dead giveaway this one: 'Is it true,' Richard asked Tom Courtenay, 'that you were born looking like a Martian?'

But the rest of the time, they are camp but suburban, naughty but nice. Their current show on Channel 4 starts at 5pm with an elderly audience inherited from Countdown and ends at 6pm with a predominantly teenage demographic. They are all things to all men. If the world was about to end, Richard and Judy would be there telling us to look on the bright side and, because it was them, we would.

They are back at the top of the TV game, but only just. Two big things happened in 2001 - 9/11 and the shock departure of Richard and Judy from ITV's This Morning show, which they had presented for 13 years. Discontented with Maureen Duffy, the show's new boss at ITV, they had allowed themselves to be poached by Channel 4 to save the otherwise rather dead 5-6pm slot. This time is known as 'shoulder peak', as it is the moment when ratings should start to climb from daytime to peak levels, and it is notoriously tricky for schedulers to negotiate. Richard and Judy were a very expensive gamble - their deal was the biggest commission ever given to an independent production company.

It was so big that Cactus, the independent producers, built Richard and Judy their own studio complex. It is in central but seedy Kennington, a little enclave of media grooviness hidden in the bleak streets. Students in a big demonstration that once passed its gates spotted the man from Znarg peering out to see what was going on. The demo ground to a halt and the chant rose: 'Who do we want? Judeee! When do we want her? Now!' Judy put on a sensible coat and stepped out to acknowledge the mob.

Not surprisingly, in view of the neighbourhood, squarish men in black suits patrol the reception area. The staff all wear name tags round their necks, their first names printed big enough to see from 20ft away. It's an attempt to put guests at their ease by relieving them of their need to remember names. There are lavish dressing rooms, offices, a big editorial floor and a phone room to take viewers' calls. They get so many calls that, if you ring the Channel 4 number, the machine offers two choices: Richard & Judy or all other programmes. It takes about 100 people to produce the show every day.