More than half the British public believe the decision to invade Iraq was wrong and more than a fifth believe Tony Blair should be tried as a war criminal, according to a poll conducted to mark the 10th anniversary of the conflict.

A majority (56%) of the public believe the war has increased the risk of a terrorist attack on Britain. More than half, (53%), of those questioned think the invasion was wrong, while just over a quarter (27%) think it was right, according to the YouGov survey.

The poll registered a marked gender differences, with almost a third (32%) of men approving the invasion compared with less than a quarter (23%) of women.

Half of those questioned said they believed Blair deliberately set out to mislead the British public about the threat posed by weapons of mass destruction (WMD). Less than a third (31%) say he genuinely believed Saddam Hussein possessed a stockpile of WMD.

More than a fifth (22%) believe Blair knowingly misled parliament and the public and should be tried as a war criminal over the conflict, according to the poll. The figure compares with almost three in 10 (29%) who say he was right to warn of dangers of the Hussein regime, 18% who think he misled people but we should move on and 15% who believe he did not intend to give false information about the threat.

The poll records that a decade after the invasion 41% think Iraqis are better off than they would have been under Hussein, and just over a fifth (21%) believe the Iraqis would have been better off under the dictator. However, more than seven in 10n (71%) say Iraq is likely to be a permanently unstable country over the next few years.

In 2010, as the Chilcot inquiry was under way, hearing highly critical evidence about how Britain went to war, 37% thought Blair should be tried for war crimes, according to a ComRes poll at the time.

At the time of the invasion, 53% of those polled said they believed military action against Iraq was right.

YouGov questioned 1,684 British adults for its poll. Fieldwork was undertaken from 10–11 March. The survey was carried out online. YouGov has published online all 10 years of its research about the conflict