Some of the biggest names on the web have written to Peter Mandelson to express "grave concerns" about elements of the Digital Economy Bill.

Four firms including Facebook and Google object to clause 17 of the bill, which could give government the power to amend copyright law in the future.

"We urge you to remove Clause 17 from the bill," the letter read.

According to the Department for Business, the clause will "future-proof online copyright laws".

The consortium, which also includes Yahoo and eBay, believe that if the clause is approved it will give "any future Secretary of State unprecedented and sweeping powers" to amend copyright laws.

"This power could be used, for example, to introduce additional technical measures or increase monitoring of user data even where no illegal practice has taken place," the letter read.