In total, between 17 December 2013 and 8 December 2014, 74 victims were persuaded to transfer their pensions, in full or in part, into bank accounts controlled by the Giles, Phelan and Bashforth.
The total amount transferred was £3,701,813.92 and they also defrauded HM Revenue and Customs out of £700,000 in tax owed, said police.
Giles also pleaded guilty to a further charge of cheating the public revenue after the court heard he had not filed a tax return for six financial years between 2008 and 2014.
A total of £834,509.75 owed by Giles – a figure which excludes interest – remains outstanding the court heard.
Sentencing him, Judge Belcher said that while a letter he had written to her was “eloquent” he had failed to address the effect his offences had on his victims.
“The impact was enormous, shock and distress and a great deal of anxiety – they were already struggling by way of wanting to release their pensions.”
Giles was sentenced to 11 years and disqualified from being a company director for 12 years.
Judge Belcher said that while Bashforth, of Spen Lane, Gomersal, was not the ringleader, he “allowed himself to be used”.
He was sentenced to five years and disqualified from being a company director for eight years.
Speaking after the sentencing, Ramona Senior, head of the Yorkshire and Humber Regional Organised Crime Unit said: “This was a complex and protracted investigation, but I am pleased that the jury were able to see that the intentions of those convicted were dishonest.”
She added: “Driven by greed, they sought access to pension holders’ cash and treated the funds they obtained as pots of money which they dipped into at will, with no intention to properly invest the funds or highlight the tax liabilities created.”