Unsigned pop-punk band Koopa became the first unsigned group to have a top 40 hit under new rules governing Internet music sales on Sunday.
The trio's single "Blag, Steal & Borrow" entered the chart at number 31 on the back of Internet download sales alone, according to the Official UK Charts Company.
Under the old rules, downloads only counted towards an artist's chart position if a physical copy of their single was on sale in the shops.
The Essex band - brothers Ollie and Stu Cooper and Joe Murphy - have built a fanbase through the Internet and concerts. They have yet to sign a contract with a record label.
Their success was overshadowed by the death last Sunday of the Coopers' father, Martin, an avid supporter of the band who suffered a fatal heart attack.
Koopa's sound has been likened to American band Blink 182 and the English groups McFly and Busted.
Elsewhere in a top 40 dominated by newcomers, reality TV show winner Leona Lewis kept the number one spot with A Moment Like This.
She held off Proper Education, a reworking of Pink Floyd's Another Brick in the Wall: Part II by Swedish DJ Eric Prydz.
British singer Mika, tipped to be one of the biggest new faces of 2007, entered the chart at three with Grace Kelly.
London rapper and singer Just Jack was another new entry at four with Starz in Their Eyes.
At five was boy band Take That with a former number one, Patience, while American singer JoJo's Too Little Too Late climbed more than 20 places to six.
British girl group Booty Luv slipped one place to seven with "Boogie 2Nite".
Falling three places to eight were rappers Akon and Eminem with Smack That, while dance DJ Sharam dropped to nine with PATT (Party All The Time).
German band Cascada's Truly Madly Deeply was at 10.
