The singer launched a rant on her MySpace blog against file-sharing, branding it "music piracy" and claiming that it was turning the British music industry into "nothing but puppets paid for by Simon Cowell", as it made it "harder and harder for new acts to emerge".
Allen, 24, wrote: "I think music piracy is having a dangerous effect on British music, but some really rich and successful artists, like Nick Mason from Pink Floyd and Ed O'Brien from Radiohead, don't seem to think so."
Mason and O'Brien contributed to a recent newspaper article as members of the Featured Artists Coalition, asking that commercial and private file-sharing be treated separately, and campaigning to find a new approach for individual file-sharers that enables the industry to make money from it, rather than criminalising them.
"I've just finished paying off all the money I owe my record company. I'm lucky that I've been successful, but not everyone's so lucky. The more difficult it is for new artists to make it, the less new artists you'll see and the more British music will be nothing but puppets paid for by Simon Cowell."
She added: "Obviously I'm going to benefit from fighting piracy, but I think without fighting it, British music is going to suffer."