Teenagers are masters at outsmarting their parents - so when Lee Denny's told him "strictly no house parties" while they were on holiday, he organised a music festival in the back garden instead.

Lee, then 17, was used to taking the opportunity to have all his mates round for a party when mum and dad went away every year.

But when they finally put their foot down, he came up with a novel new way to make the most of an empty house, and LeeFest was born.

Now in its fourth year (and this time with full parental backing) LeeFest has snowballed into a huge charity event in a nearby field next to Langley Park Boys School.

"My parents went on holiday one year and previously we used to have lots of house parties when they went away," says Lee, now 21.

"Just before they went that year, they sat me and my friends down and gave us a strict talking to. They said no more house parties because we'd wrecked the carpets a couple of times and the neighbours had complained.

"Being young and a bit bolshy, we thought it would be ok to have a festival because it wasn't a party. We thought we'd get away with it.

"About an hour after my parents left, everyone moved into my front room and started organising the event. My house became Camp Festival."

Lee and his friends held the festival in his garden in Beckenham, with performances from bands from around the local area.

"All of the local bands and audience of 150 people were friends of ours in the first year."

Luckily Lee's parents were more impressed with their son's ingenuity than annoyed at his rule breaking.

"They were forgiving and thought it was quite funny.

"My parents were there the second year in the garden, keeping a watchful eye on it and last year they came down and did bits and pieces around the site. This year they're coming down again."

LeeFest has morphed into a bigger and bigger event each year.

"We've got a pretty small back garden so the second year it was a bit of a squash, but it was with my parents' permission and we got 350 people."

Last year they left the garden for the first time and set up camp in a field bordering the school the organisers used to go to, Langley Park Boys.

And this year Lee's expecting record numbers, with a capacity of 1,500 people.

"The main core of people who organise it have always been the same. They're Alex Brooks, David Hayes, Richard Legate, Squib Swain for the last two years, and now my little brother Andy. Most of us are good friends from school."

And LeeFest isn't just about the music - each year they've raised money for a chosen charity, with the amount steadily rising each time.

The festival is completely not for profit, with all proceeds going to the chosen charity.

In the first year they raised £250 for the Teenage Cancer Trust, the second year was £500 for Save the Children and last year they reached the £1,000 mark for Age Concern.

This year's chosen charity is the London-based Kids Company, which provides practical, emotional and educational support to vulnerable inner-city children and young people, and Lee says they're aiming to double the amount fundraised last year.

Lee, who's just finished a physics degree at Nottingham University and is hoping to become an actor, has secured some big name acts this year that include The Holloways and Sam Isaac.

But they're also staying true to their roots of giving local performers a platform.

"Last year we branched out a bit with the size of the festival and this year we've got professional bands in and our headline act is The Holloways. It's really nice to have professional bands playing side by side with the best local unsigned bands.

"Lots of people are looking forward to seeing The Holloways on our stage, it's pretty amazing. Personally I'm looking forward to seeing two local bands, Golotus and Kid Id. A1 Bassline from Croydon will be playing the dance arena."

Organising a festival is a huge achievement and something Lee and his friends have enjoyed and built up each year.

So what was Lee's favourite memory from last year's LeeFest?

"Last year I really enjoyed going to bed!

"I was doing 24 hour security and there was £100,000 worth of sound equipment in one of the marquees and I was so scared it was going to get stolen that I slept on top of it.

"I remember looking back over the day as I went to sleep. I was thinking about seeing people happy and smiling at the event we'd organised."

LeeFest is on Saturday, August 15 opposite Langley Park Boys School, Hawksbrook Lane, Beckenham.

Tickets £20 from www.gigantic.com, under 13s get in free with a paying adult.

For more information go to www.leefest.org.uk.