A fixation with celebrities has been blamed for an apparent ignorance of politics and current affairs among the British public.
Celebrity culture is harming political knowledge, the survey says
Almost half of those questioned for a Whitaker's Almanack survey could not name the deputy prime minister.
John Prescott was correctly identified by 53% of people, but 31% said they had "no idea" who the deputy PM was.
Almanack editor-in-chief Lauren Simpson said: "We are a nation obsessed with celebrity culture."
Ms Simpson said everybody needed to "escape from real life" once in a while.
"[But] I would like to see more people putting down their celebrity gossip magazines... to keep abreast of current affairs and the world around us," she said.
Is this a musician or the United Nations secretary general?
The level of knowledge was worse among younger people, with just 27% of those in the 16-24 age group able to name Tony Blair's deputy.
Some 80% of those questioned said they were nervous and embarrassed about their lack of political knowledge - and Ms Simpson said Britons were right to worry.
More people identified Kofi Annan as United Nations Secretary General than correctly named the deputy prime minister, according to the survey.
Some 58% named Mr Annan - but some thought he was an Iraqi general, the South African president, an athlete or musician.
More than 1,000 adults were questioned across the UK for the Omnibus survey.