Outside Edge: Rosie Millard on Folkestone's festival - the light at the end of the tunnel

Adrian Evans sits in his basement flat in London and waves a huge file of papers in French and English; detailing plans for one of the largest outdoor arts extravaganzas in England this decade.

The Channel Tunnel will be officially opened by the Queen on 6 May (though the public won't be able to use it until June). But on 7 May, to mark the opening, Eurotunnel, the developers, have commissioned Evans to create a festival of live performance for a crowd of 150,000 in Folkestone, site of the English entrance. Evans, the former producer of Archaos, the radical French circus, and director of London's Latin American festivals, Gran Gran Fiesta], is painfully familiar with the problems of raising finance for public extravaganzas. Yet Eurotunnel simply said they had the money and asked him to devise a day to remember.

Sited on the seafront in Folkestone, the day will start with a procession, on the theme of transport, involving over a thousand locals. It ends seven hours later with a massive firework display.

Live acts will punctuate these events. 'I decided to focus on the benefits of the tunnel, the positive side of having a closer union with France,' says Evans. Two stages will provide six hours of 'good-time music', half British, half French folk-rock. Meanwhile, using the sea as a backdrop, French trapeze artists will be spinning from a 60ft free- standing trapeze rig; and a customised lorry will unfold to reveal a 'high-wire and cloud-swing' show.

'Oh yes,' continues Evans casually, 'a specially created hot air balloon will be hanging around nearby, with a trapeze artist swinging from the basket. And then there's an English aerial ballet group.' On the ground there is a 'grandiose show and marine animation' from Les Plasticiens Volants, last seen at the Barcelona Olympics finale, incorporating people on stilts, pyrotechnics and a vast inflatable octopus. 'There is also a fun-fair, a vintage car run, the appearance of Thomas the Tank Engine and, erm, a sausage which is as long as the tunnel itself - 26 miles.'

'I've deliberately avoided using household names,' says Evans. 'This is more Sidmouth Folk Festival, than that awful night in Docklands with Jean-Michel Jarre. This is a fantastic chance to introduce them to new elements of French and British culture. You would have needed a vast amplification system if someone like Sting had been booked, and the whole event would have been somewhat aggressive, rather than celebratory.'

The day is thought to be setting Eurotunnel back pounds 1m. But then, being Eurotunnel, no one is prepared to put a more exact figure on it.