Zahid Iqbal and Sharfaraz Ahmed were jailed for up to 16 years in Britain
The men, all from Luton, had admitted one count of engaging in conduct in preparation for acts of terrorism between January 1 2011 and April 25 2012 at a hearing on March 1.
Ringleaders Iqbal and Ahmed were given extended terms of 16 years and three months, including 11 months in jail.
Mr Justice Wilkie QC said the two men posed “a significant risk of serious harm to the public.”
Arshad was jailed for six years and nine months and Hussain for five years and three months.
Iqbal and Ahmed spoke about making an improvised explosive device (IED) based upon instructions in an al Qaida manual entitled “make a bomb in the kitchen of your mom – by the al Qaida chef”, the court was told.
Covert recordings of the pair heard Iqbal suggesting attaching the bomb to a remote controlled toy car and sending it under the gap of a gate to a Territorial Army (TA) centre in Luton.
Iqbal was recorded telling Ahmed: “I was looking and drove past like the TA centre, Marsh Road. At the bottom of their gate there’s quite a big gap.
“If you had a little toy car it drives underneath one of their vehicles or something.”
The men were arrested following a series of raids at their homes in April last year after an intelligence-led joint operation by the Metropolitan Police Counter Terrorism Command and the British Security Service (BSS).
Their persistent commitment to terrorist activity… marks them out as particularly dangerous
Ahmed was observed by surveillance on “numerous occasions” going on trips to mountainous regions such as Snowdonia with others in preparation.
The judge said: “In each of their cases, their persistent commitment to terrorist activity, in a number of different ways, over a significant period of time and, in each case, their willingness to take practical steps to obtain terrorist training abroad, marks them out as particularly dangerous.
“This, coupled with the fact that, after their houses had been searched, and they were obviously under serious suspicion, they nonetheless continued to access material consistent with the mindset which informed their previous preparatory activities, persuades me that they continue to be “dangerous” to such a degree that I should exercise my discretion to pass an extended sentence.”