Six men from the West Midlands have been jailed for up to 19-and-a-half years each for planning to bomb an English Defence League rally.
Omar Khan, Jewel Uddin, Mohammed Hasseen, Mohammed Saud, Zohaib Ahmed and Anzal Hussain had all admitted terrorism offences in April.
Five of them had taken a bomb, knives and sawn-off shotguns to last June's rally in Dewsbury, West Yorkshire.
But the plotters arrived two hours after the EDL event had ended.
The men, who all lived in or near Birmingham, were caught by chance after a car being used by two of them, and carrying weapons, was stopped by police on the M1 after the rally and found to have no insurance.
At the Old Bailey, Khan, Uddin and Ahmed were sentenced to 19-and-a-half years in jail, with a five-year extension on licence.
Hasseen, Hussain and Saud were jailed for 18 years and nine months, with a five-year extension on licence.
Extended sentences, introduced in England and Wales last year, mean offenders serve at least two-thirds of their main sentence in custody. After release, they are on licence in the community for the rest of their sentence plus the extension part.
The six defendants received a reduction of a quarter in their jail terms for pleading guilty before a trial had been due to start.
Sentencing the men, Judge Nicholas Hilliard QC said their device - an 18in nail bomb using explosives from fireworks and stuffed with shrapnel - had been a "horrible weapon" that would have caused serious if not fatal injuries.
He said it had not been an amateurish attempt but wide-ranging and determined.
As well as targeting EDL supporters, police officers and members of the public could have been caught up in the attack, the court heard.
The judge said had the attack succeeded, it could have sparked "a spiral of tit-for-tat violence".
Judge Hilliard told the men: "How was it that you became involved in a crime of this gravity? At least part of the answer to that question must come in the tide of apparently freely available extremist material in which most of you had immersed yourselves."
The judge said the extremist material was "not difficult either to obtain or share".
"In this case, it can only have served to reinforce the defendants' resolve to behave in the hideous way that was planned," he said.
'Extremely dangerous men'
EDL leader Tommy Robinson and his deputy Kevin Carroll called out "God save the Queen" from the public gallery as sentence was passed.
Sobs could be heard from other observers, and shouts of " Allahu Akbar" - "God is great" in Arabic.
The men, with the exception of Hasseen, had travelled to Dewsbury on 30 June last year.
The gang's plan failed only because the EDL rally finished earlier than expected - they arrived at about 1600 BST when it had finished shortly after 1400, the court heard.
Judge Hilliard said: "There is no reason to suppose that a further attempt may not have been made in the future had the defendants not been apprehended. I find it inconceivable that your resolve would have evaporated."
Assistant Chief Constable Marcus Beale, from West Midlands Police, said the men had planned an "horrendous attack" and "probably would have killed people and definitely caused lots of injuries".
"I think the level of sophistication of the weapons was relatively low but their operational sophistication was very high, which meant they were difficult to catch," he said.
"I don't see them as jokers. I see them as extremely dangerous men who deserved to be brought to justice."
Two of the men, Khan and Uddin, were stopped as they travelled back to Birmingham from Dewsbury.
A police officer pulled their car over because it looked old, and it was flagged up as uninsured because the registration number had been entered incorrectly on an online form by one digit.
The car was taken to a pound and staff discovered the weapons two days later. The arsenal included two shotguns, swords, knives, a nail bomb containing more than 400 pieces of shrapnel, and a partially-assembled pipe bomb.
As well as the weapons, the men had 10 copies of a note referring to Prime Minister David Cameron and the Queen.
It also called the EDL the English Drunkards League, and in a direct message said: "Today is a day of retaliation (especially) for your blasphemy of Allah and his Messenger Muhammad."
Five of the men were from Birmingham - Uddin, 27, Khan, 28, and Hasseen, 24, all from Sparkhill, Ahmed, 22, from Alum Rock, and Hussain, 25, from Moseley - and one, Saud, 23, was from Smethwick.