A 49-year-old man from Leeds has been sentenced to three years and nine months in prison for possessing a handwritten recipe for gunpowder.
Martyn Paul Gilleard, from Town Street in Armley, was sentenced at Leeds Crown Court on Monday, October 20, 2025.
He will serve an additional four years on extended licence and will be subject to a Serious Crime Prevention Order for five years, along with terrorism notification requirements for ten years.
Gilleard admitted possessing information likely to be useful to someone committing or preparing an act of terrorism under Section 58 of the Terrorism Act 2000. The document was discovered at his home during an intelligence-led search by West Yorkshire Police on May 28 and referred to Counter Terrorism Policing North East for investigation.
Detective Chief Superintendent James Dunkerley, head of Counter Terrorism Policing North East, said in a statement that “officers were concerned to discover a handwritten recipe for black powder during a search at Gilleard’s home in May; a recipe later verified by experts as potentially viable.”
He added that “possessing information about the manufacture of explosives will always raise serious questions. Gilleard has chosen not to explain or defend the presence of the recipe in his home, instead pleading guilty to possessing information useful to a person committing or preparing an act of terrorism.”
The recipe for black powder (gunpowder) is very simple (only 3 ingredients) and is very easily obtained from Open Sources. I am somewhat concerned that intent to use this information for terrorist purposes has not been demonstrated, yet a conviction with a long sentence has resulted.
Might this man just have been a bit curious? Seems like he had a hopeless defence counsel.
Did he have a proper defence I wonder?
Although, as pointed out down the page, he did have previous for nail bombs which is pretty significant….
I personally find it a very scary overreach of state power.. it’s telling that it’s not actually illegal in regards the the explosives act to have the 1000 year old recipe for black power ( that a lot of people have for reason of historic study). What they are using is the various terror acts that are profoundly open to abuse… I personally believe the terror legislation and anti hate legislation are profoundly warping the power balance between state and individual and are more than a bit anti the values of the UK. Before the terror legislation it was only against the law to make the stuff without a valid legal use.. the terror acts essentially mean you can be found guilty because of the knowledge you hold.. that is close to the ministry of love.
And yet under the Explosives Act 1875, the making of small quantities of gunpowder for experimental purposes is legal.
Problem is that the Terrorism legislation is so broadly and badly drafted as to make thought pre crimes: crimes.
Unless there is more to this story, the conviction and sentence are ridiculous. Everyone with first year chemistry knows how gunpowder is made. Anyone else can Google it.
Exactly my thoughts.
There are loads of older chemistry text books that explain how to make it – they also explain how to make TNT….although that is next level dangerous chemistry….
The recipes for those nitrate explosives aren’t complicated either, although the consequence of getting them wrong can be very abrupt and final. To try and mitigate that risk, HMG has been cheerfully inconveniencing the people they’re supposed to serve by restricting the availability of nitric acid- not that this would pose much obstacle to anyone with both malevolent intent and a modicum of ingenuity.
Very true!
Very much more to the story – the man reportedly has a history with nail bombs.
I used to buy mine from the shops in the run up to Bonfire Night. The recipe was walk into a s**p, hand over m***y, walk out with gunpowder-filled f*******s. I wouldn’t want to get any of you arrested, so I’ve redacted the crucial information.
Did I fall asleep for months and its actually 1st April? When I was at school, many, many years ago, I used to make gunpowder and make my own fireworks. It was called fun. The “recipe” was freely available in many childrens science books. There must be more to this suerly?
There is more to the story – previous 16 year prison sentence in 2008 for making nail bombs.
Which should have been reported….
Yeah, that little detail seems very important for context.
So his crime is writing the ingredients down?
Maybe he had the intent with him pleading guilty.
Interesting story the way it is reported. I have several text books with this information. There is however much more information which contributed to the sentence. At best this is disingenuous which to the average Joe is called click bait. Disappointing.
No in the end in this case they arrested tried and charged a man for holding a recipe that is not illegal to hold and is in many books.. they used the terror laws to warp what was legal or illegal for him as an individual.. he was held to a different standard of law as everyone else because he was a Neo Nazis and had previously been convicted… but there was no evidence of a plot, he had not breached the explosives act etc… essentially what he did was only illegal be he did it.. if I had done it there would have been no conviction.. that is terrifying.
As everyone else has said – but could use reinforcement- making black powder is slightly easier than making coffee. That could not have been the full extent of the prosecution case unless he had the world’s worst defence lawyer.
No the reality was this man was a horrible Neo Nazi with previous convictions.. but they arrested him and found him guilty for holding the recipe.. a recipe that is widely known and in many publications.. they used terror laws to essential hold this man to a different standard of justice than they would have say a member of the sealed knot or someone who just likes the history of firearms. As far as I’m concerned that is essentially anti the rule of law and Anti the values of the UK.. if they had found any evidence of him making Black powered or planning an attack that’s fine..
This is one of those cases that makes me worry about the direction our nation is going in, because as far as im concerned this is anti the rule of law pure and simple.. case they arrested, charged tried and found a man guilty was for holding a recipe that is not illegal to hold and is in many books.. they used the terror laws to warp what was legal or illegal for him as an individual.. he was held to a different standard of law as everyone else because he was a Neo Nazis and had previously been convicted… but there was no evidence of a plot, he had not breached the explosives act etc… essentially what he did was only illegal because he did it.. if I had done it there would have been no charge or conviction, because I would not have been doing anything illegal….because I would have been legally tested under the explosives act….that is terrifying because we are all meant to equal under the blind eyes of the law, it’s literally the fundamental building block of our nation and culture, the rule of law.