Mika, winner of the BBC's Sound of 2007 survey of new talent, has the highest new entry at three with his single Grace Kelly, while Eric Prydz was at number two with Proper Education.

The second highest new entry was Just Jack at four with Starz In Their Eyes, pushing Take That's Patience to number five.

Amy Winehouse climbed to the top of the album chart with her latest offering Back to Black.

James Morrison's Undiscovered rose three places to number two, Snow Patrol's Eyes Open was a non-mover at three and Take That's Beautiful World fell from the top slot to number four.

Koopa have benefited from a change in chart rules introduce on the 1 January.

Before that date an artist needed to release singles on CD or another physical format - and therefore have a record deal - to qualify for the chart.

Record deal

Singer and bassist Joe Murphy told the BBC News website it was all down to their manager and "awesome" fans.

"Without them we would not have done it," he said.

"Just four days ago nobody had heard of us, now it seems like everyone has. I can't get my head around it."

Murphy added that they had been contacted by a number of big record labels, including one who recently turned them down.

There is also talk of a US label flying them out to America for talks.

Koopa, from Colchester, have been together for seven years in various forms and have built up a fanbase on the internet and on the live circuit.

They have played almost 500 gigs in the past three years, including a headline show at the Mean Fiddler in London last summer.