The swoop was terrific. With his arms spread out in front of him, his hair and dressing gown streaming out behind him, he dived down out of the sky, bellied along a body of air about two feet from the ground and swung back up again, catching himself at the top of the swing and holding. Just holding. He stayed there.

It was wonderful.

And that, he realized, was the way of picking up the bag. He would swoop down and catch hold of it just at the point of the upswing. He would carry it on up with him. He might wobble a bit, but he was certain that he could hold it.

He tried one or two more practice swoops, and they got better and better. The air on his face, the bounce and woof of his body, all combined to make him feel an intoxication of the spirit that he hadn’t felt since, since - well as far as he could work out, since he was born. He drifted away on the breeze and surveyed the countryside, which was, he discovered, pretty nasty. It had a wasted ravaged look. He decided not to look at it any more. He would just pick up the bag and then… he didn’t know what he was going to do after he had picked up the bag. He decided he would just pick up the bag and see where things went from there.

He judged himself against the wind, pushed up against it and turned around. He floated on its body. He didn’t realize, but his body was willoming at this point.

He ducked down under the airstream, dipped - and dived.

The air threw itself past him, he thrilled through it. The ground wobbled uncertainly, straightened its ideas out and rose smoothly up to meet him, offering the bag, its cracked plastic handles up towards him.

Halfway down there was a sudden dangerous moment when he could no longer believe he was doing this, and therefore he very nearly wasn’t, but he recovered himself in time, skimmed over the ground, slipped an arm smoothly through the handles of the bag, and began to climb back up, couldn’t make it and all of a sudden collapsed, bruised, scratched and shaking in the stony ground.

He staggered instantly to his feet and swayed hopelessly around, swinging the bag round him in agony of grief and disappointment.

His feet, suddenly, were stuck heavily to the ground in the way they always had been. His body seemed like an unwieldy sack of potatoes that reeled stumbling against the ground, his mind had all the lightness of a bag of lead.

He sagged and swayed and ached with giddiness. He tried hopelessly to run, but his legs were suddenly too weak. He tripped and flopped forward. At that moment he remembered that in the bag he was now carrying was not only a can of Greek olive oil but a duty-free allowance of retsina, and in the pleasurable shock of that realization he failed to notice for at least ten seconds that he was now flying again.

He whooped and cried with relief and pleasure, and sheer physical delight. He swooped, he wheeled, he skidded and whirled through the air. Cheekily he sat on an updraught and went through the contents of the hold-all. He felt the way he imagined an angel must feel during its celebrated dance on the head of a pin whilst being counted by philosophers. He laughed with pleasure at the discovery that the bag did in fact contain the olive oil and the retsina as well as a pair of cracked sunglasses, some sand-filled swimming trunks, some creased postcards of Santorini, a large and unsightly towel, some interesting stones, and various scraps of paper with the addresses of people he was relieved to think he would never meet again, even if the reason why was a sad one. He dropped the stones, put on the sunglasses, and let the pieces of paper whip away in the wind.

Ten minutes later, drifting idly through a cloud, he got a large and extremely disreputable cocktail party in the small of the back.

The longest and most destructive party ever held is now into its fourth generation, and still no one shows any signs of leaving. Somebody did once look at his watch, but that was eleven years ago, and there has been no follow-up.

The mess is extraordinary, and has to be seen to be believed, but if you don’t have any particular need to believe it, then don’t go and look, because you won’t enjoy it.

There have recently been some bangs and flashes up in the clouds, and there is one theory that this is a battle being fought between the fleets of several rival carpet-cleaning companies who are hovering over the thing like vultures, but you shouldn’t believe anything you hear at parties, and particularly not anything you hear at this one.

One of the problems, and it’s one which is obviously going to get worse, is that all the people at the party are either the children or the grandchildren or the great-grandchildren of the people who wouldn’t leave in the first place, and because of all the business about selective breeding and regressive genes and so on, it means that all the people now at the party are either absolutely fanatical partygoers, or gibbering idiots, or, more and more frequently, both.

Either way, it means that, genetically speaking, each succeeding generation is now less likely to leave than the preceding one.

So other factors come into operation, like when the drink is going to run out.

Now, because of certain things which have happened which seemed like a good idea at the time (and one of the problems with a party which never stops is that all the things which only seem like a good idea at parties continue to seem like good ideas), that point seems still to be a long way off.

One of the things which seemed like a good idea at the time was that the party should fly - not in the normal sense that parties are meant to fly, but literally.

One night, long ago, a band of drunken astro-engineers of the first generation clambered round the building digging this, fixing that, banging very hard on the other and when the sun rose the following morning, it was startled to find itself shining on a building full of happy drunken people which was now floating like a young and uncertain bird over the treetops.

Not only that, but the flying party had also managed to arm itself rather heavily. If they were going to get involved in any petty arguments with wine merchants, they wanted to make sure they had might on their side.

The transition from full-time cocktail party to part-time raiding party came with ease, and did much to add that extra bit of zest and swing to the whole affair which was badly needed at this point because of the enormous number of times that the band had already played all the numbers it knew over the years.

They looted, they raided, they held whole cities for ransom for fresh supplies of cheese crackers, avocado dip, spare ribs and wine and spirits, which would now get piped aboard from floating tankers.

The problem of when the drink is going to run out is, however, going to have to be faced one day.

The planet over which they are floating is no longer the planet it was when they first started floating over it.

It is in bad shape.

The party had attacked and raided an awful lot of it, and no one has ever succeeded in hitting it back because of the erratic and unpredictable way in which it lurches round the sky.

It is one hell of a party.

It is also one hell of a thing to get hit by in the small of the back.