Britons could be sleepwalking into a new era of state surveillance powers, judging by a new poll conducted by the civil rights organisation Liberty.

Before a Commons battle over the investigatory powers bill this week, the poll found that 92% of respondents who were aware of the proposals – described as a “snooper’s charter” by critics – disapproved of them. But 72% of respondents said that they knew nothing about it.

The two-day Commons report stage of the bill, which will increase the powers of the intelligence services, is scheduled for tomorrow and Tuesday and is the final major piece of parliamentary business before the EU referendum is held.

On Thursday the home secretary, Theresa May, announced a series of concessions in an attempt to woo Labour and Liberal Democrat critics, whose alliance with backbench Tory opponents mean the government cannot rely on its slim Commons majority. May’s fresh safeguards include the introduction of a “privacy clause” meant to ensure that the new mass-surveillance powers are not authorised in cases where other, less intrusive, means could be used.

The snooper’s charter would compel telecoms companies and internet service providers to store every person’s communications data, including records of calls, texts, emails and their entire internet browsing history for a year. The data could be used by dozens of public bodies.

Critics say that it is only justifiable for the government to monitor emails, texts, phone calls and online browsing history if a particular individual is suspected of criminality or has committed a crime.

The poll was commissioned by campaign group Liberty, which believes that only targeted access to communications data based on suspicion, alongside a robust system of independent judicial oversight, can be justified when tackling serious organised crime.

Bella Sankey, director of policy for Liberty, said: “This bill would create a detailed profile on each of us which could be made available to hundreds of organisations to speculatively trawl and analyse. It will all but end online privacy, put our personal security at risk and swamp law enforcement with swathes of useless information.”