Gideon Komolafe, aged 36, and Simon Kogoro, 40, were sentenced to four and a half years last Tuesday and the following day 39 year-old Wilton Clarke was given 18 months.
They had previously been found guilty of conspiracy to commit fraud.
Komolafe and Kogoro were also jailed for an additional year for committing a similar fraud against a high street bank.
In May the court heard how in 2006 the fraudsters used personal information available from Companies Houses to trick UK and Indian call centre operators into handing over Aviva account numbers for the director’s life assurance policies.
The fraudsters, who are all from Woolwich in South East London, used this information to cash in the policies and transfer across £638,000 into fraudulent bank accounts set up in the director’s names.
The money was then moved into business accounts registered in Kogoro’s and Clarke’s names, and finally transferred into the men’s personal accounts.
At this point Aviva’s security measures alerted them to the fraud and the insurance group launched an investigation.
They later called in the City of London Police and officers uncovered the chain of bank accounts that led directly back to the fraudsters.
After arresting Komolafe in July 2007, officers searched his home and uncovered evidence that he and Kogoro had committed a similar crime against a customer of a high street bank.
Documents showed the two men had targeted some of the banks’ high value customers.
A fraudulent account had been set-up in a customer’s name and £150,000 had been transferred from another customer’s account.
But, due to bank security policies this transfer was picked up and the money was returned.
City of London Police Economic Crime Directorate detective constable Jeffrey Gettings says: “By working closely with the financial institutions involved we were able to unravel the trail of clues that led to Komolafe, Korogo and Clarke and ensure they were brought to justice.
“The prison sentences handed to these three men should be a serious warning to others. If you are convicted of fraud you can expect a number of years in jail.”
An Aviva spokeswoman would not reveal the names of the directors that were victims of the fraud, but says: “We are pleased that the fraudsters who perpetrated this crime have been given significant sentences.
“Hopefully this will act as a serious deterrant and a warning to others.”