'Their plans for the intercept modernisation programme were completely unworkable to begin with - and are becoming more so with every addition they suggest.
'The idea of tracking calls, texts and emails made by people in the country is unspeakably offensive.'
The social networking websites have attracted the interest of security chiefs because they are not covered by rules drafted in Brussels after the 2005 London bombings to track terrorist activity in emails and on the internet.
Social networking companies - also including Bebo - would be required to retain details of every contact a user corresponds with via their websites.
Facebook has 17million UK members while Bebo and MySpace have 10million each.
Liberal Democrat Home Affairs Spokesman Tom Brake blasted the combined EU and UK proposals as a 'snooper's charter' - and pointed to the Government's track record of losing sensitive digital data...