A 70-year-old man, who amassed one of the largest known collections of indecent images in England and Wales, has been jailed for more than 12 years.
Prosecutors told York Crown Court that Geoffrey Crossland had amassed more than 2.2 million indecent images of children.
Police officers investigating the case also found prohibited firearms and ammunition in a secret underground bunker, made of shipping containers, beneath Mr Crossland's house in Harrogate, North Yorkshire.
North Yorkshire Police said the seizure of the indecent photos included 6,946 in the most extreme category, A.
The pensioner had earlier admitted to three counts of making indecent photographs.
On Monday he admitted 11 counts in relation to the possession of firearms and ammunition.
He was sentenced to 12 years and eight months at York Crown Court, as judge Andrew Stubbs QC said the "scale of the depravity" the images depicted was hard for the public to understand.
"Your criminality was unearthed, almost literally, on October 18 last year, when officers searched your house for images of children," the judge said.
"One issue which is not forgotten is that these images capture real life people, and at the same time real life sexual abuse being carried out on them."
A court heard how the pensioner had "painstakingly categorised" the images and had written himself lists of the best websites from which to access sexual pictures and videos of children.
Prosecutors described how Mr Crossland had demonstrated a "long-standing interest in children", with the earliest images dating back to 1998.
Officers discovered a shooting range and an area designed for the manufacture of ammunition in the 70-year-old's bunker.
He had also stored 24,000 rounds of ammunition beneath the his home.
“The CPS worked closely with North Yorkshire Police from the start of this large, complex...operation. The sheer quantity and nature of the images discovered is deeply shocking, and without parallel in North Yorkshire," Julian Briggs, from the CPS, said.
"It is one of the largest hoards of such material ever discovered in England and Wales.
“That alone would make this case extraordinary and troubling.
"But the subsequent discovery of prohibited firearms and ammunition, concealed in underground bunkers at Crossland’s home clearly shows that this defendant is a highly dangerous individual.
“The sentence handed down today indicates the severity of Crossland’s offending.”
Susannah Proctor, defending, said in court that there was no evidence Mr Crossland had any intention to cause harm with the weapons and ammunition.
Additional reporting by agencies
