Hundreds of letters claiming a group ply young girls with drugs before taking them to hotels for sex have been delivered in a sinister smear campaign.

The letters, written in English, Gujarati and Urdu, gave the names and full addresses of four members of a Blackburn family, along with details of a male friend.

The letters urges the community to watch out for the father and son who borrow money on the behalf of women and do not pay it back.

Copies were sent to houses from Beardwood to Audley Range on last Thursday.

Main target of the poison pen letters, who asked to remain anonymous, said: "It is untrue from the first word down to the pathetic thank you' at the end of it. This letter is nothing but vile lies. This is more than a hate campaign. It is disgusting.

"The letter is hugely damaging to all those mentioned in it."

Those involved have contacted solicitors and will consider taking legal action if the culprit is found.

Detective Inspector Jim Elston said people receiving the letters should not try and take the law into their own hands.

He said: "We have been notified about the content of these letters and whoever has written and distributed them is wholly irresponsible.

"To conduct a campaign targeting individuals in this way is unacceptable and whoever is involved has not considered the wider consequences of their actions."