Video report by ITV News Security Editor Rohit Kachroo

Members of a terrorist cell who dubbed themselves the "Three Musketeers" have been found guilty of plotting a Lee Rigby-style attack.

The partly-secret Old Bailey trial, which was plagued by accusations of police corruption, heard that the gang, from the West Midlands, were poised to strike police and military targets on British soil.

They were arrested in August last year after MI5 bugged the car of Naweed Ali and uncovered a pipe bomb and meat cleaver hidden in a JD Sports bag.

Ali, 29, Khobaib Hussain, 25, and Mohibur Rahman, 33, claimed the incriminating evidence was planted by an undercover officer known as Vincent, who posed as the boss of a fake firm called Hero Couriers.

But all three were unanimously found guilty after the jury deliberated for 22 hours.

A fourth defendant, Tahir Aziz, 38, was also found guilty of preparing terrorist acts after the jury deliberated for another 20 minutes.

They will be sentenced on Thursday.

Tahir Aziz was the newest recruit to the cell. Credit: West Midlands Police / ITV News

Speaking exclusively to ITV News following the guilty verdicts, the father of one of the men, Khobaib Hussain, said that he felt "saddened" and "angry" by the situation and that his son did not have the capabilities to plan something like this.

Detective Chief Superintendent Matt Ward, head of West Midlands Counter Terrorism Unit, hailed the verdict as a success.

He said: "Today's case was about four very dangerous extremists who were plotting to carry out a terror attack in the UK.

"Today the communities of the Midlands, Stoke-on-Trent and Birmingham should feel relieved that they are much safer with these four dangerous individuals now going to spend a long time behind bars."

As they were led from the dock, one of the convicted men shouted out: "I hope you're happy with your lies. Lying scumbags."

The 'Three Musketeers' and how they attempted to evade detection

The gang were surveillance aware and sometimes left their mobile phones at home. Credit: West Midlands Police

The jury had heard how the gang called themselves the Three Musketeers on encrypted Telegram exchanges.

It was led by former law degree student turned trainee gas fitter Hussain, from Birmingham, and included his friend and next-door neighbour Ali and committed jihadist Rahman, who they met behind bars.

Ali and Hussain were jailed for joining a terrorist training camp in Pakistan while Rahman, from Stoke, was in prison for possessing an al Qaeda propaganda magazine which contained bomb-making instructions.

Family man and Primark salesman Aziz, who was keen not to be "left behind", was only brought into the plot just days before the arrests.

The gang had tried to evade secret services and police and even attempted to double deal with an MI5 contact of Rahman's to extract information.

The defendants were also covertly photographed meeting on a boating lake and in a park days before their arrests, the court heard.

How the plot was foiled by counter-terror officers

Police found this secret stash of weapons. Credit: West Midlands Police

The authorities were one step ahead of the group with an elaborate undercover operation at Hero Couriers, where Hussain and Ali were offered driving shifts.

On 24 August, Hussain appeared restless and complained to Rahman: "We gota do something akhi (brother) just nothings really happening."

Two days later, Ali arrived for his first shift at Hero Couriers and left his Seat Leon car at the Birmingham depot before MI5 moved in to conduct a search and "technical" operation - bugging the vehicle.

Ali's car at the depot in Birmingham where a stash of weapons was discovered. Credit: West Midlands Police

Instead, they found the JD Sports bag in the foot well containing a partially-constructed pipe bomb and meat cleaver with the word "kafir" - non-believer - scratched on it in readiness for an imminent attack.

An imitation gun, cartridges, a 9mm bullet, latex gloves and industrial tape were also recovered.

Police immediately arrested all four men and seized a large sword which had been stashed in Aziz's car.

Police found a meat cleaver with the word Credit: West Midlands Police

Ali, who had previously claimed to have been wooed by MI5, declined to give evidence in his defence.

Ringleader Hussain, who lived next door to him in Sparkhill, Birmingham, told jurors he only believed in "defensive" jihad.

Aziz, from Stoke, claimed he was just doing research when asked to explain what he was doing with pages from an al Qaeda pipe bomb-making article. He also claimed the sword in his car was for self-defence.

His sister believes he was set up.

Speaking to ITV News, Nazreen Khan said: "He doesn't deserve to have a name tag as a terrorist. "

When asked if Aziz ever mentioned extremist ideology or jihad, she said: "No. It's always on the news every day, so basically everybody gets to see it.

"If he's streaming any videos... a lot of people do stream videos but it doesn't mean that they are linked to terrorists."

The trial held in secret over security fears

The terror cell were secretly filmed by security services in Birmingham. Credit: West Midlands Police

In the third recent case of its kind at the Old Bailey, the trial was partly held behind closed doors to avoid putting security services on the spot in public.

Two of the defendants claimed "persistent, unwelcome and oppressive" approaches by MI5 and MI6 to become informants in 2015 and 2016.

While their claims could be aired, the Home Secretary issued a certificate before the trial saying two unnamed witnesses should be heard in secret.

The trial was also disrupted over fears jurors might be unfairly influenced as the country was rocked by four terror attacks in Westminster, Manchester, London Bridge, and Finsbury Park.