In the run up to the anniversary of war in Iraq, more condemned the recent Gulf conflict than attacks on America.
And almost half said they might consider becoming a suicide bomber if they lived as a Palestinian.
An overwhelming 80% say Britain and the US should not have launched the invasion that toppled Saddam Hussein.
That is significantly higher than the 73% opposed to terrorist strikes on the US, according to the ICM survey for The Guardian.
Attacks on the US by al Qaida or other groups were viewed as justified by 13% of the 500 British Muslims questioned.
Another 15% said they did not know whether the such attacks are wrong or right.
Far fewer, 10%, said Prime Minister Tony Blair and US President George Bush were right to go to war.
Liberal Democrat MP Jenny Tonge provoked fury when she said that despite condemning violence living as a Palestinian could have driven her to become a suicide bomber.
However, 47% of Muslims agreed compared with just 15% of all of those questioned.
Ms Tonge’s comments were rejected by 43% of Muslims and 78% of all voters.
Continuing Islamic hostility to the war is costing Mr Blair support at the polls.
Backing for Labour among British Muslims has slipped from 75% at the last election to just 38%, the poll showed.
However, overall the party remains ahead on 37% despite a fall of one point on last month.
Conservatives are up one on 35% while the Liberal Democrats remain on 21%.
The Muslim Council of Britain said the poll shows most British Muslims “abhor” terror attacks.
And if a minority believe the US deserves to suffer more such attacks, that shows the US is losing trust.
Iqbal Sacranie, general secretary of the council, said the poll results surprised him, particularly the 13% who feel further attacks on the US would be justified.
And he stressed most of the people polled were questioned before the terror attacks in Spain.
“My gut feeling is that the poll is not right or fair,” added Mr Sacranie. “The 13% reflects emotions are running high.
“But the percentage of Muslims that would support attacks when they are taking place would be much much lower.”
He said: “British Muslims are much more frustrated than the general population with US foreign policy.
“At the end of the day it’s a Muslim population around the world on the receiving end of trouble and bias in terms of US policy.”
One of Britain’s most radical Muslim leaders said he believed the majority of Muslims in the UK supported al Qaida-style terror attacks on the United States.
Sheikh Omar Bakri Muhammad, who heads the London-based group Al-Muhajiroun, said British Muslims were afraid to voice their real feelings about the coalition war in Iraq.
And he claimed that far more were pro-Osama bin Laden than really admitted.
“I am sure the real figure who support al Qaida is much higher than one in 10.
“Since the introduction of the new anti-terrorism laws, Muslims are terrified to speak their minds.
“I believe it is the majority of Muslims in the West who support al Qaida. This is beyond doubt.
“The role of the suicide bomber in Palestine is a noble one – to fight for freedom for his people and become a martyr. Why is it strange for Muslims to want to be part of this?”
ICM questioned 500 Muslims between March 3-11 and another 1,014 other adults between March 10-11.