The government has set a secret target to reduce illegal filesharing of music and films by up to 80% over the next three years, MediaGuardian.co.uk can reveal.

The goal was outlined in a letter by Baroness Vadera, the business minister, to internet service providers as part of the agreement the government struck with internet service providers and the film and music industries to curb illegal file sharing.

The leaked letter, dated July 22, was sent to all...