5.30am on Saturday morning and Darlington town centre is filthy. Discarded burgers, drinks cartons, half-eaten chips and pizza boxes flow down from High Row to Northgate, swirl round outside MacDonalds and blow up to the doors of Marks & Spencer

Skinnergate is ankle deep in more fast food - much of it thrown away before it's even been touched. Here there are bottles, broken glasses and hundreds of fliers for The Lounge bar, scattered all over the pavements and hard to remove.

There are pools of vomit, puddles of lager, a few late drunks staggering home and out of the corner of my eye, I see shadowy figures scuttling down the yards and alleys.

"Skip rats," says Kenny Hardcastle, dismissively - men and women who raid the skips and bins and search the streets for what they can find in other people's rubbish.

It's another world - and Kenny clears it up.

Every morning he and his opposite number Steve Johnson are out in their little vans sweeping the streets, washing away the filth of the night before, scooping up thousands of fag ends, so that by the time we get out and about, everywhere is clean and tidy. Other people empty the litter bins and sweep underneath the benches.

"I think most people don't even realise we exist," says Kenny. "They've no idea how filthy people can be. It turns my stomach sometimes."

He was a welder blacksmith, worked for United for years and still makes decorative ironwork in his spare time, but has been doing this job for ten years. "I love it," he says. "There's a real sense of satisfaction and I think we make Darlington one of the cleanest towns in the country."

Of course, he always checks when he's in other places. "The only other place that really comes up to our standards is York - they do a very good job there," he admits.

His little machine sweeps, sucks, sprays, can cope with just about anything. It even has heavy-duty disinfectant for the lane known as "Pissy Alley". Everything except pizza boxes. We go up and down High Row, up the steps even, past the bus shelters but every time we come to a pizza box - and there are an awful lot of pizza boxes - Ken has to get out and pick them up by hand.

He knows all the early morning people, recognises the security men, works round the delivery drivers. High Row got a quick going over first this morning as the men were putting up market stalls there.

He says there are four people sleeping rough in Darlington and he knows them all and which doorways they choose. "They're no problem at all," he says, "It's the druggies I don't like. They're high as kites and totally unpredictable."

The subway near the car parks used to be full of discarded needles, but it's not been so bad lately. "Maybe they've moved somewhere else," he says.

He's seen some sights. Couples having sex in telephone boxes, runners racing through the town centre stark naked, plenty of fights. But he just tootles along in his little van, cleaning up.

Up and down Skinnergate. Back and forth. The little van can turn on a tanner. It takes a long time as there is just so much rubbish. So much it blocks the pipes. Ken gets down and unblocks it. "Horrible job," he admits.

When he goes home, he gets stripped off by the back door and then straight into the bath. He always washes work away before he does anything else.

But gradually the mound of rubbish disappears. The street is restored to the way we normally see it.

Steve and Ken are out seven days a week. They were out on Christmas Day and will be out on New Year's Day. "Not as bad as it used to be as people don't seem to celebrate they way they used to," he says.

Everyone else's celebrations always mean more work for them. Weekends are worst, but Friday mornings are getting bad now too. Thursday night seems to be the big drinking night in Darlington.

The best days, says Ken, are summer mornings. "I like a really early start - you have to because otherwise you wouldn't get the job done. Then you can see the sun rise and it's good to be out then when you have it all to yourself and there's no- one else about."

There are surprises too. In the middle of one of Darlington's car parks - surrounded by the blowing polystyrene boxes, the shredded newspapers and the rolling, clanking lager bottles, is a pear tree. "We had wonderful fruit off there last year," he says.

And last Saturday, Ken pointed out anther treasure - a little patch of mushrooms flourishing among the rubbish. "When we're out in the early hours, we see a side of Darlington that no-one else knows about."

So sometimes, even among the muck, there's a bit of magic too.

But the real magic is the state of the streets by the time the town wakes up. Next time you're in Darlington, notice the streets, notice how clean they are. Remember that it took a lot of hard work to get them that way.

And next time you have a pizza - please, please don't just drop the box.