An Old Bailey judge praised Daily Mirror investigative reporter Andrew Penman whose work helped smash a £1 million fraud gang.
Penman secretly filmed the gang who targeted unemployed people who wanted to get heavy goods vehicle licences.
Instead of providing a service, the gang stole the money before disappearing.
Judge John Bevan said at the sentencing hearing: “It is not often that I get a chance to congratulate journalists, but this was a genuine piece of investigative journalism.
“The actions Mr Penman took in filming the gang provided a thoroughly dramatic piece of evidence.”
Penman exposed the gang in December 2011 after covertly filming members of the conspiracy in action.
The evidence obtained by the Mirror was used by Tower Hamlets trading standards officers who were able to bring a successful prosecution.
Judge Bevan added: “The victims were vulnerable. They may not have been elderly or frail – but they were poor and wanted to spend a lot of money in order to provide them with a skill.”
Members of the gang were jailed for between four and six years.