It should have been the mother of all free music festivals - and one in the eye for the hated Criminal Justice Act. But things soon started to go wrong.

The idea had been floating around for months. In April it was decided that the "seventh of the seventh" would be the day that travellers, ravers and party-goers would prove that the Criminal Justice Act was unworkable.

At nightfall last Friday thousands of hedonists had planned to descend from all points of the compass on a secret festival site and hold a week- long party. Dancing, music and alternative philosophies were to combine in a heady mixture to overthrow the hated Act. The police were supposed to realise that repression was futile and that the time had come to allow people to hold their festivals without harassment.

Party-goers and organisers hate the Criminal Justice Act because it criminalises unlicensed free parties and festivals. More than 20 people gathering without the land-owner's permission on land to which the public has no, or only a limited, right of access, constitutes an illegal gathering.

Police can exclude anyone within a five-mile radius whom they suspect of trying to attend a party, while the organisers can be jailed for three months and fined pounds 2,500. Sound systems can be seized and the police can demand money for their return or destruction. Party-goers can be fined pounds 1,000.

In addition, the Act removes the "right to silence", gives the police increased stop-and-search powers (similar to the old "sus law") and provides for the setting up of a comprehensive DNA database.

In April, a meeting between members of a sound system and an underground civil rights group was held. They agreed that the best way to break the Act was to prove that it was impotent. Over the coming months the underground was buzzing with news of the "seventh of the seventh". Everyone wanted to be involved. Party people from around the country pledged their support - and their sound systems - to the festival. Small civil rights groups gave help and began organising locally.

No central organisation was established because of fears that it could be infiltrated. The date was simply fixed and the rest left up to individual groups to organise locally and co-ordinate nationally. Slowly, it was hoped, everything would coalesce to form the mother of all festivals.

Everyone knew the risks. If the police identified any prominent figures, conspiracy charges would certainly follow. If they were caught at the festival, then sound systems could be confiscated, heavy fines imposed and the presumed organisers imprisoned.

To avoid any fear of conspiracy charges, news of the festival was initially propagated by word of mouth only and was therefore untraceable. The idea was to build up support without making any specific plans. It is a tried and tested system - gain support for the idea, then provide the specific details at the last moment and so minimise the chances of getting caught. .

Flyers started appearing two months ago. They called for the downfall of the Act on the "seventh of the seventh" and listed contact telephone numbers where information would be left on answering machines in the days leading up to 7 July. The tapes were changed regularly, each time giving just a few more snippets of information.

Sound systems and travellers then began to think of the best site. Prominent members of the movement held a meeting in a disused factory in South London last Tuesday evening. The final plans were laid.

A site near Corby, Northamptonshire, was selected. A mixture of old light industrial land and open fields, massive and secluded - it was the perfect. It had six entrances and so, it was hoped, would stop police closing it off with road-blocks. The site was to be "cracked" at 3am on Friday. Maps were given out, memorised and destroyed.

But there was almost immediate disagreement. People from the South West had their own site and wanted to use it. After frantic discussion it was agreed to hold two festivals, offering, it was thought, twice the challenge to the authorities. The other site, at a disused airfield at Smeatharpe, East Devon, was not to be cracked until midnight on Friday. The plan was that, if the Corby festival were broken up, then everyone could head South and join the Smeatharpe rave.

Cars and trucks began streaming towards Corby late on Thursday night. They formed ever larger convoys and an advance party of 50 vehicles occupied the site at 3am. Other smaller convoys lay in wait in Northamptonshire.

At midday on Friday the messages on the answering machines were changed: callers were told to head to the Midlands and ring back at 3pm. Hundreds of vehicles were heading for the area when the local police moved in and cleared the site after receiving "certain intelligence information".

The convoy of travellers then headed for "Site B" at Sleaford in Lincolnshire. The convoy of old buses, trucks and beat-up old cars - most of them clearly on their last legs - moved at a stately 25mph along a dual carriageway. Rust, bits of bodywork and number plates scattered the roadway as, every few miles, the whole convoy had to halt to allow an old bus or truck to cool down. Each time the convoy stopped, another few vehicles would join up. The same was happening in Cambridgeshire. Two other convoys were busily expanding and heading in the same direction. The police were getting twitchy.

In London, two people suspected of organising the events were having their doors kicked in. Debbie Staunton, a member of the United Systems, was taken in for questioning. Michelle Poole, of the anti- Criminal Justice Act group, Advance Party, was taken away, questioned and later charged with conspiracy to cause a public nuisance.

The police then took over the phone lines. People ringing in for directions were surprised to find themselves being quizzed. Normally information is just handed out, no questions asked. Now callers were being asked to give their names, telephone numbers and information about their travelling companions. On leaving, the police left the phones off the hook, crippling half the party network's communications system. A back-up system was kicked in.

Many in the convoys had mobile phones and their numbers were common currency - used by scouts looking for sites and by party-goers trying to join up to one of the convoys. But then, mysteriously, all the mobile phones stopped working simultaneously.

There was only one solution: stop and have a party. The main convoy, now over a mile long, pulled off the main Kettering to Huntingdon road and wound its way through a series of Cambridgeshire villages. The locals looked on in amazement.

Eventually it reached the edges of the old RAF base at Molesworth. Now redundant, it would have been a perfect festival site. But again the convoy ground to a halt. The police breathed a collective sigh of relief and closed off the road. The travellers could, they said, spend the night on the road if they wished. The police wanted to keep the convoy moving but they were also keen to stop it meeting up with other convoys and holding an impromptu rave.

At the new site sound systems were unloaded, generators started and several hundred people began to party in earnest as the sun went down. The party- goers of two other convoys over the border in Lincolnshire did the same.

In the South-west the police had mounted Operation Ornament. Units were mobilised throughout Devon and Cornwall and the Smeatharpe festival broken up before it even started. Roving bands of travellers and party-goers set up impromptu gatherings across the South-west.

They may not have broken the Criminal Justice Act but that wasn't going to stop anyone having a good time. Lessons have been learnt and among dedicated party-goers there's already talk of organising the next Big One.