LONDON — They were very ordinary would-be terrorists, with big plans but bad luck.
On Thursday, a jury convicted three young British men — including an unemployed pharmacy graduate nicknamed Chubbs — of being ringleaders of an Al Qaeda-inspired plot to explode knapsack bombs in crowded parts of Birmingham, England’s second-largest city.
The men had pleaded not guilty, but were recorded discussing plans for attacks.
A jury at Woolwich Crown Court in London found 27-year-old Ashik Ali; Irfan Khalid, also 27; and 31-year-old Irfan Naseer — nicknamed Big Irfan, or Chubbs — guilty of multiple counts of preparing for terrorism.
Judge Richard Henriques told the men they face life in prison when sentences are imposed in April or May. ‘‘It’s clear that you were planning a terrorist outrage in Birmingham,’’ the judge said.
But the men failed — thanks in part to official surveillance and their own incompetence.
Prosecutors said Naseer and Khalid traveled to Pakistan for training, learning the details of poisons, bomb-making, and weaponry, and made ‘‘martyrdom videos’’ justifying their planned attacks.