A Pembrokeshire-led project is hoping to break world records today, getting 600,000 school children all over the UK singing simultaneously.

David Lewis, who lives works in Solva, founded Young Voices 12 years ago to promote communal singing in schools.

His team set the Guinness world record for the planet's biggest singalong in 2005. Three years later David is determined to smash that record.

"There are around 600,000 children registered to take part but that can change dramatically on the day," said David. "It's a bit of a lottery."

"We've always said we want to get to a million, this may happen in a few years but 600,000 is far more than we have had singing together before."

Today's Big Sing will be led live from London's 02 Arena by 90s singing sensation Des'ree . All one million schoolchildren will join with her in singing a specially commissioned version of her worldwide smash hit ''You Gotta Be' .

When Des'ree left pop music to concentrate on other projects she said she would never sing that particular track again.

However, she simply could not turn down the opportunity to get involved in the Big Sing, which will benefit charities Youth Music, Marie Curie Cancer Care and CLIC Sargent, and so she will take to the stage to sing it one last time today.

David's team contacted 24,800 education establishments earlier this year in the hope that 2,500 take part and break the one million barrier.

In 2005 four Pembrokeshire schools took part in the record breaking singing session. This year Pembrokeshire's participation in the project has ballooned, with around 15 schools taking part.

Among those flying the flag for the county at this afternoon's event are children from Broad Haven, Fishguard, Hayscastle, Johnston, Manorbier, Milford Haven and Stepaside.

Two Guinness adjudicators will be in each school. Each child is asked to contribute £1 to take part which will then go to charity.

David emphasised that the most important thing was to get children singing: "I think the most important thing of all is that children should be enabled to enjoy music," he said. "It's educational and if you love music it's going to help you throughout your life."

The IT infrastructure, support and promotion of the event is being coordinated by Milford Haven's NACAL solutions.

The Big Sing kicks off at 2.45pm today. Log onto the website later this week to see if the Pembrokeshire-led project will smash its own record.