Axel Rudakubana had enough ricin to kill over 12,000 people, having purchased the materials years ago.

Yesterday, the killer was sentenced to jail for the murders of Alice da Silva Aguiar, nine, Bebe King, six, and Elsie Dot Stancombe, seven.

He was also charged with 10 of attempted murder for those he injured, as well as possessing a knife, the poison ricin and an al-Qaida manual. He unexpectedly changed his plea to guilty on all charges on Monday.

According to experts, the quantity of the biological toxin ricin found in his home would have been enough to kill up to 12,690 people through inhalation after a “further purification process”.

It also had the potential to produce up to five lethal doses via ingestion or to kill between 1,500 and 7,600 via injection.

The poison was discovered in a Tupperware box underneath his bed, which contained a then-unknown substance. Later, experts confirmed it to be ricin, a potentially fatal toxin produced using castor beans, 150 of which he had purchased online in early 2022.

Around the same time, Rudakubana bought a pestle and mortar, two funnels, and a scientific flask from Amazon. These were among a group of seized items from his bedroom, including a machete and arrows.

Other items found in his home include a knife identical to the one used during the murder of the three young girls. It was in the living where Rudakubana was said to have been sleeping at the time.

Two tablet computers were also seized, which were found to contain materials, including a PDF file entitled: “Military Studies in the Jihad Against Tyrants: The Al-Qaeda Training Manual", which "contained advice and instruction on committing acts of terror".

Deanna Heer KC, prosecuting, told the court yesterday: "The material found on these devices provides, the prosecution suggests, a window into the defendant’s mind at this time.

"It shows that he was fascinated with violence of an extreme nature, that he had obtained information on killings and how to kill and obtained weapons capable of killing. The evidence demonstrates that the stabbings on that day were premeditated and had been planned by the defendant for several weeks."