A poll of nearly 2,000 Britons by YouGov/PHI found that 70 per cent of respondents incorrectly said it was true that the US had done a worse job than the European Union in reducing carbon emissions since 2000. More than 50 per cent presumed that polygamy was legal in the US, when it is illegal in all 50 states.
The poll was commissioned by America In The World , an independent pressure group that launches on Monday and aims to improve understanding and appreciation of the US in Britain and around the world.
Tim Montgomerie, its director, said factual inaccuracies and mistaken assumptions have contributed to Britons and Europeans taking a hostile stance towards their most powerful ally, which often acted against national interests.
"We wanted to find out how British people understood America and found that there was an unbalanced view. Maybe there are good reasons but if we cleared a lot of that factual ignorance we would have a better understanding of what America really is," said Mr Montgomerie, who also founded the influential ConservativeHome website three years ago.
The survey showed that a majority agreed with the false statement that since the Second World War the US had more often sided with non-Muslims when they had come into conflict with Muslims. In fact in 11 out of 12 major conflicts between Muslims and non-Muslims, Muslims and secular forces, or Arabs and non-Arabs, the US has sided with the former group. Those conflicts included Turkey and Greece, Bosnia and Yugoslavia, and and Kosovo and Yugoslavia.
Asked if it was true that "from 1973 to 1990 the United States sold Saddam Hussein more than a quarter of his weapons," 80 per cent of British respondents said yes. However the US sold just 0.46 per cent of Saddam's arsenal to him, compared to Russia's 57 per cent, France's 13 per cent and China's 12 per cent.
"Ideas get around. Perhaps it's that old picture of Donald Rumsfeld with Saddam," suggested Mr Montgomerie, whose website includes a petition against anti-Americanism.
"Hollywood and all its violence has something to do with it, and the awful Bush diplomacy," he added.
Almost a third of Britons believe that "Americans who have not paid their hospitals fees or insurance premiums are not entitled to emergency medical care"; by law such treatment must be provided.
More than half the respondents believed that polygamy is legal in some US states, while it is illegal in all US states.
Most Britons were unaware of positive aspects of the US, such as the robust environmental movement or the social justice work of evangelical churches, he said.
Apart from US-bashing being a favourite topic around European dinner tables, it has serious affects on national policy.
The controversial missile defence shield in eastern Europe might have happened sooner with a more favourable climate, while public opinion helped Turkey's leaders deny the Americans an invasion route into Iraq from its territory, aiding the northward flight of elements of the Saddam regime.
