Customs officials tipped off about an illegal shipment of machine guns to Kuwait raided a £1.5m house in Kent to find dozens of shredded documents.
A Koch MP5 similar to those Knight brokered between Iran and Kuwait
They believed they related to an operation by arms dealer John Knight to move 130 guns from Iran to Kuwait even though he had been refused permission.
The officers spent months painstakingly piecing the shredded paper together.
Their work resulted in evidence which put Knight, 52, from Fawkham, behind bars for four years.
"It was quite amazing," said Malcolm McHaffie, lawyer for the Revenue and Customs Prosecution Office (RCPO), which took the case to court.
"The judge was quite astonished at what was done."
Mr McHaffie said Knight was an established arms dealer - one of a large number across the world.
He had brokered a deal between arms manufacturer Tusa, based in the Iranian capital, Tehran, and Al-Boury, an agency in Kuwait.
The $120,000 (£58,000) deal was arranged through his company, Endeavour Resources Ltd, based in the British Virgin Islands.
But when he applied for a licence from the UK Export Licensing Authority in November 2006, he was turned down.
He laid a paper trail to make it look as though he had pulled out of the deal but it went ahead - and was intercepted in Kuwait.
Knight pleaded guilty to the illegal sale of the guns at Blackfriars Crown Court in September and was jailed on Friday.
He was also ordered to pay a £54,389 confiscation order.
The prosecution was the first under The Trade in Goods (Control) Order, which came into force in May 2004.
It was designed to prevent the uncontrolled movement of arms by British nationals outside the UK.
Although the paperwork was handled by Knight in Kent, the guns never actually reached Britain.
As well as the shredded documents and faxes that proved the deal went ahead, Customs investigators recovered emails from his computer hard drive.
"Small arms trafficking is estimated to result in 500,000 deaths a year all over the world," said McHaffie.
"The legislation followed a UN arms conference in New York in 2001."
He said arms dealing was a worldwide business, but for the UK authorities there was a particular interest in the Middle East because British troops were engaged in combat there.