Plans to allow the authorities to monitor the online activity of every person in Britain were pushed back after being condemned by MPs from all parties.
The Deputy Prime Minister, Nick Clegg, announced that the contentious measures would be published only in draft form and would be subject to widespread consultation - concessions that could delay the proposals for at least a year.
In a letter to Clegg published in the Independent yesterday, 17 Liberal Democrat MPs welcomed his intervention but warned him their support could not be taken for granted.
A storm erupted this week after it emerged that legislation to allow the police, intelligence services, councils and other public bodies to obtain details of messages sent via Skype and social networks would be included in the Queen's Speech.
The disclosure provoked anger among Tory and Liberal Democrat MPs alike, who warned that the proposals contradicted the parties' opposition to a similar Labour scheme - and were not included in the Coalition Agreement.