LONDON (AP) - Leading British technology companies are lashing out against a British bill that would allow copyright holders to force Internet service providers to block websites offering pirated content.

Top officials from companies including Google, Facebook, eBay, Yahoo!, and Virgin as well as academics and others have written a letter to the Financial Times to argue against a bill now working its way through the parliament's upper house.

The proposed law would allow copyright-holders to seek injunctions blocking websites alleged to be hosting pirated content.

Yesterday's letter said such a change would "threaten freedom of speech and the open Internet".

But the BPI, which represents Britain's piracy-hit music industry, dismiss the warning as "pure scaremongering".