HMRC released covert surveillance from their investigation.
Fraudsters in a large-scale tax scam were caught on camera bragging about the scale of their crimes.
At one point, one of the fraudsters brags of their "Aladdin's cave" and how they would make the national news, if they were caught.
The ringleaders of the fraud that led to Northern Ireland's largest ever tax inquiry and took a decade's worth of investigation were jailed.
Francis Devlin, 58, and Paul McStravik, 56, were sentenced to a combined eight years on Tuesday, bringing the total number of people sentenced in connection to the case to 27.
The investigation lasted over a decade, and involved the use of secret recordings in a bugged accountant's office.
The fraud was a large scale operation, involving a 27 member gang who created 16 bogus companies and used 56 associated bank accounts.
They created a false audit trail to allow clients to operate in the construction agency without paying VAT or tax.
The case against Devlin and McStravick relied in part on six weeks of secret surveillance and over 260 hours of footage.
The footage shows gang members planning the fraud at the Belfast, Lisburn Road accountancy firm Allen Tully & Co, at which Devlin was a partner.
The investigation into the case involved the PSNI, the PPS, the National Crime Agency and HMRC.
Over 400 HMRC officers searched 34 businesses and residential premises, including three in England.
Along with the ringleaders, 25 accomplices were given suspended prison sentences. Many of these knowingly allowed their personal details to be used as part of the fraud.
Richard Las, Director of the HMRC's Fraud Investigation service said that the gang ran a "sophisticated and complex fraud" that required NI's largest ever tax probe to "bring it down."
He said the "tenacity and expertise" of HMRC fraud investigators "has stopped the loss of millions of pounds in taxpayers’ money, which is now paying for our vital public services, rather than lining the pockets of criminals.
“The fact is, no tax criminal is beyond our reach and that includes those corrupt professionals who aid and abet them, as these sentences clearly show."
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