The group, headed up by Donald McLeod, of Middlesex, fraudulently manipulated the accounts of their haulage and heavy plant hire business to hide millions of pounds in customer VAT payments so they could siphon it off for their personal gain.

An HMRC investigation showed more than £16m had passed through their company accounts between 2004 and 2012.

During that time they had siphoned off £4m in VAT payments, set up false business bank accounts and used a deceased associate’s account to launder the cash.

John Cooper, Assistant Director, Criminal Investigation, HMRC, said: “This criminal group thought they had developed the perfect plan to steal from the UK taxpayer and launder their profit without detection or having to face the consequences.

“They were wrong and are now paying the price.”

In September 2012 officers from HMRC arrested the four and searched 15 domestic and business premises across London and the south of England.

Computers, mobile phones and business records were seized, along with £37,500 cash. Around 100 HMRC officers took part in the arrest and search operation.

The Middlesex and North London-based companies – DM Services, DJM Services Ltd, O’Connor Plant and Heavy Trans Ltd – which fronted the fraud carried out high-profile work including erecting the Christmas lights at Covent Garden and clearing waste from the London 2012 Olympics’ site.

All four were charged with Cheating the Public Revenue.

Confiscation proceedings are now underway to reclaim their criminal profits.

Details of the defendants sentenced at Southwark Crown Court:

Donald McLeod (DOB 04.04.62) of Dorchester Way, Hayes, Middlesex UB4, was found guilty and sentenced to seven years imprisonment and disqualified from being a company director for 10 years.

William Gallacher (DOB 18.03.68) of Sussex Way, London N19, was found guilty and sentenced to five years and nine months imprisonment.

Arthur Spring (DOB 28.02.59) an Irish national of Brewery Close, Wembley, Middlesex HA0, pleaded guilty and was sentenced to three years and nine months imprisonment and disqualified from being a company director for 10 years. Spring used various aliases as part of the fraud, including Neil Doherty.

Edward Corr (DOB 03.11.63) an Irish national of Monks Park, Wembley, Middlesex, pleaded guilty and was sentenced to three years and nine months imprisonment and disqualified from being a company director for 10 years. Corr used various aliases as part of the fraud, including David John Mangan.