Benicassim: A trip to the Spanish music festival makes a rock holiday to remember

After the wettest June in the UK since detailed records began in 1914, and festival-goers leaving the Glastonbury mud bath early, a gathering with guaranteed sunshine, sandy beach and all-night parties – and a line-up to match any of this year's British festivals – is alluring.

Known to many as Glastonbury-on-Sea, or Glasto del Sol to its native residents, the Spanish Benicassim festival – situated in a small resort town between Barcelona and Valencia on the eastern coast and now in its 13th year – is becoming increasingly popular with British music fans. At his show on Saturday evening, Jamie T's announcement that 65 per cent of the festival-goers this year are British is met with mass nationalistic cheering. Sixty-five per cent is perhaps an exaggeration, but there's no denying that the place is full of Brits.

Benicassim increased its huge British fanbase last year when, in the absence of Glastonbury, it sold out for the first time. This year's alternative pop, rock and electronica festival attracted a record 150,000 people. Also testimony to its growing success, Mean Fiddler's founder Vince Power last year bought a majority share in the festival.

On the flight to Valencia, there seem to be plenty of people on their way to Benicassim. One person is bragging about his awaiting air-conditioned hotel room, while the rest of us face the prospect of roasting in tents in 30C to 40C heat.

For the many British fans who attend, the experience is more than a festival – it is their summer holiday. The three campsites open four days early to allow people to extend their break, and many people are planning to stop off at nearby Barcelona afterwards. One girl I meet walking to the festival site, a student at the University of West England, tells me: "It's my summer holiday. There was a group of us deciding between Exit in Serbia and Benicassim. I chose Benicassim because it's on the beach."

Delphine, a record label business support analyst, who moved from Paris to London for the music scene, has been coming to the festival for the past six years. "It's cheap, it's by the sea, it's in Spain. It's always been a way to have a cheap holiday, and for people who like music I think it's perfect. Here it's constantly warm."

There is a distinctly carefree holiday atmosphere. Because of the weather, people are in a great mood and it shows at every gig. It's far too hot for indie skinny jeans. Instead, everywhere people are decked out in colourful beach clothes. By 10am it is too hot to sleep in a tent and a steady stream of people in shorts and bikinis head to the beach to snatch a few more hours' shut-eye in the sun and cool off in the sea. Here, and sitting outside the resort's many cafés, is where festival-goers spend their daylight hours.

The festival site itself is deserted until 5pm. Because of the overpowering heat, very few acts take to the stage before 9pm, and the headliners aren't on until after 1am. Venture back to the festival area at 9pm and the site has been transformed into a buzzing hub. By midnight, the entire site is a party, music blaring from every stage and people dancing, arms in the air.

Those who aren't dancing are sitting and chatting on every small patch of grass, soaking up the atmosphere as they watch giant screens showing the performances or dipping their feet in the small floodlit pool. After the headline acts have finished, the site becomes a dance arena, with different beats pumping out of every venue until 7am. The temperature is still close to 30C.

There are a couple of alt.country acts, including Bright Eyes, Calexico and Wilco, who play a typically powerful set on the main stage on Friday night, and Amy Winehouse does show up to play on the Sunday, thwarting all the unfounded rumours circulating at the festival that Lily Allen would be her replacement.

With the exception of the headlining rock acts Arctic Monkeys and Muse, this year's Benicassim reflects the rise of "new rave" and electronica. Exceptionally popular acts of the moment, such as the Klaxons, The Rapture, CSS, Jamie T and the Sheffield headliners, have pulled in younger-than-average crowds to the festival. But international acts such as Wilco, Herman Dune, Os Mutantes, and Peter Bjorn and John have still attracted the discerning older music fan. Influential veteran dance acts including B-52s and Devo, who perform in orange tin hats and yellow boiler suits, and Thursday night's star performers Iggy and the Stooges, provide both intrigue and nostalgia.

Sets by indie dance acts The Rapture, the Klaxons and CSS are received with more energetic enthusiasm than could ever be seen at a gig. Perhaps not quite realising the popularity of such bands the Klaxons and CSS, the festival organisers have mistakenly put them on the smaller Fiberfib.com tent instead of the main stage. If you're lucky enough to make it into the seething crowd, there is at least some respite from the fine cooling mist sprayed from the tent roof.

Brazilian electro rock band Cansei de Ser Sexy are welcomed to a stage full of candy-coloured balloons on Saturday night by a chanting crowd. Their single "Alala" is a favourite. There are even some brave souls who risk a tumble on the concrete floor and attempt to surf over the crowd's sweaty hands. Lovefoxx, suited in her usual catsuit, exclaims: "This is the best crowd we've ever had." And she's probably telling the truth.

Headline acts Arctic Monkeys and Muse draw the biggest crowds at the 55,000 capacity main stage area. Headlining on Saturday night, Arctic Monkeys – even more in demand after being nominated a second time for the Mercury Music Prize last week, – play hits from across their two albums, including "I Bet You Look Good on the Dancefloor", "Fluorescent Adolescent" and "When the Sun Goes Down", to rapturous applause. The final night, Muse headline, wrapping up an evening of rock from Kings of Leon and Black Rebel Motorcycle Club.

And on Monday night, there is the legendary farewell beach party – that is, for those who can last that long. Benicassim really does live up to its reputation of being the wildest festival.