´óÏó´«Ã½

Sky has warned some of its customers they are likely to receive letters demanding cash for illegally downloaded pornographic films.

The letters, from the Golden Eye company, which has previously targeted O2 customers, threaten legal action.

While Sky stops short of telling users not to pay, it advises them to "carefully read the letter".

The practice of so-called speculative invoicing has been criticised by judges and solicitors in other cases.

Speculative invoicing is defined by the Citizens' Advice Bureau as a "pay up or else" scheme in which "some unscrupulous solicitors and companies... target subscribers to internet services and demand payment from them for copyright infringement to avoid having to go to court".

Sky said Golden Eye had "successfully applied for a court order against Sky".

This required the internet service provider (ISP) to hand over the names and addresses Golden Eye had identified as being associated with downloading films illegally.

"We have written to all affected customers, advising them carefully to read the letter from Golden Eye, and if they want any further help, to contact the Citizens' Advice Bureau," Sky said.

Golden Eye director Julian Becker told the ´óÏó´«Ã½ that letters would be sent to "thousands" of Sky customers.

He denied that the company was involved in speculative invoicing, saying that "rights holders... both adult and mainstream producers have every right to protect their content and livelihood from internet thieves".

"We have only written to those account holders for whom we have evidence of copyright infringement," he said.

He added that the firm did intend to pursue cases in court if defendants did not want to settle and had issued proceedings against a number of people.

But not everyone is convinced by the firm's motivation.

Michael Coyle, who has represented hundreds of clients who have faced similar letters, said those people who receive them were in a difficult position.

"If they go to a solicitor, they will want a minimum of £500 to £700, and that is about what Golden Eye will ask for compensation, so many will think that it is easier to pay to make it go away," he said.

He advised people who received the letters to write back to Golden Eye asking what proof it had that they had downloaded the material or seek professional advice.

He said it was "unlikely" Golden Eye would take any of the cases to court as it would be very difficult for it to prove anyone had downloaded the films, without "an admittance of guilt or inspecting their hard drive".

Mr Coyle also criticised providers for "rolling over too easily" by giving IP addresses to companies who had taken infringement action previously.

"Parliament also needs to address the safeguards of this, as judges are releasing these orders far too easily," he added.

Golden Eye approached O2 customers in 2012, when it gathered a list of 9,124 IP addresses on behalf of 13 adult entertainment companies.

It was seeking £700 per film for copyright infringement.

But in the High Court, Mr Justice Arnold ruled Golden Eye could not justify sending letters demanding that amount of money.

Instead he said that each case should be "individually negotiated" and said that the letters were "capable of causing unnecessary distress because it could be read as an implicit threat of publicity once proceedings have been commenced".

The Citizens' Advice Bureau has written its .