The Revenue and Customs Prosecution Office achieved a conviction in 92% of the 1,121 cases it prosecuted in 2008/09, according to its latest annual report.
The office also obtained 499 confiscation orders against criminals amounting to over £69m, and collected almost £22m.
There were also 12 defendants sentenced to a total of 125 years in prison for drug smuggling and money laundering - the second highest achieved by the RCPO.
Other highlights include: the conviction of three men to a total of 10 years' imprisonment for trafficking military equipment military equipment to Iran in direct violation of the UK embargo.
Since its creation in 2005, the RCPO - which is currently in the process of merging with the Crown Prosecution Service - has prosecuted almost 5,500 cases and confiscated over £88m from convicted criminals.
RCPO director David Green said: 'I firmly believe that, since its launch, RCPO has succeeded in its objective of restoring public and judicial confidence in HM Revenue & Customs prosecutions, a judgment shared by Her Majesty's Crown Prosecution Service Inspectorate in their recent report.'
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