Jax repeated the process until all the Easy-Off Bam was gone. It took almost all of the Isocol to burn through the four bottles of bleach. By the time he was done, his chip packet was almost a quarter full. Plenty.

The next part was relatively easy – no sculling, scoffing or singeing himself while scooping powder out of a red-hot can. He took all four packets of the Wet Ones from his shelf and placed them next to the other half Coke can. He opened the first packet of Wet Ones and began the simple but laborious task of ringing the liquid out of each towel and into the can. One by one, he twisted, turned and squeezed each of the forty towels, until he had about 150 millilitres of pure acetone.

He now had the two ingredients that, when combined, made triacetone triperoxide, or TATP. Also called ‘The Mother of Satan’, it’s one of the most explosive molecules known to man and an explosive of choice for terrorists – it had been used in several attacks, including the London bombings in 2005. Now all Jax had to do was build his bomb.

Using the cutting tool first and then the nail clippers, Jax cut a one-inch-wide hole into the side of the toughened one-litre tin that contained the pineapple juice, poured the yellow juice straight down the sink, and rinsed out the tin as best he could, even though he knew that the juice would not react with the chemicals.

He tipped the hydrogen peroxide into the tin first – he needed all the white powder to be at the bottom – funnelling every last speck through the one-inch hole. Next he took the blades out of the remaining forty-seven BICS and snapped each one in half before feeding them all in.

Then he inserted a range of things he had been collecting since he’d decided he was going to blow them all to hell – mostly rocks taken from the yard, but also shards of glass, a handful of aluminium ring-pulls and a screw. He chucked the nail clippers in too, figuring he would never need them again. Lastly, he pushed in the four marble-sized balls that he had recovered from his own waste. He had kept them hidden in his cell since passing them, but had said he was constipated whenever Marsh asked.

He used the dregs of the Isocol to set a small fire in his trashcan. If his plan didn’t work or the bomb didn’t detonate, he couldn’t risk a guard coming across his rubbish and exposing him before he’d have the chance to try again. He watched the little blaze burn slowly, into black dust. When it was done, he doused it with water from the sink; the slushy mix that was left could have been anything, and would probably be chucked before anyone even thought to check it.