Wilmot's claims that he was not knowingly involved in the attempted VAT fraud were rejected during the trial at Southwark Crown Court.

In passing sentence, Her Honour Judge Taylor, observed that:

"It was an audacious attempt to obtain a large sum of money by fabricating evidence."

Wilmot, a Nigerian national, was also recommended for deportation upon completion of his sentence, and was also disqualified from acting as a company director for eight years.

Robert Gray, Assistant Director, Criminal Investigation Directorate, commented:

"Mr Wilmot has been sentenced today to five years imprisonment for his fraudulent attempt to steal GBP17.5mn pounds from honest taxpayers."

"Wilmot is a barrister - he was in a position of knowledge and trust. He chose to abuse his privileged position to mount an extremely serious attack on the VAT system. This massive fraud would have worked were it not for HM Revenue & Customs's (HMRC) rigorous checking of VAT repayment claims together with the diligence of local HMRC staff."

Wilmot claimed to be a barrister specialising in shipping, aviation insurance and international tax laws. He was arrested following an investigation triggered by his first VAT Return, which contained a repayment claim for over GBP17.5mn.

Discrepancies on his VAT return triggered checks and a call on his chambers by an HMRC VAT Officer, the UK tax authority revealed. Wilmot tried to argue that the massive VAT repayment claim was due to the purchase of jet engines from a UK company, Aircraft Unit Engineering Ltd, which he had sold to an Iraqi businessman.

He also claimed the engines were shipped on the Heroi Strakhorskyi, from Southampton on 12th December 2006 for the port of Umm Quasr, Iraq.

Wilmot provided paperwork for sales and shipping, but was unable to show any bank accounts relating to payment for the engines.

HMRC explained in a statement that:

"Further enquiries showed the VAT number on the invoice from Aircraft Unit Engineering Ltd was a redundant VAT number belonging to the Argos Catalogue company. The Aircraft Unit Engineering company does exist but its declared VAT returns show its sales are not of the magnitude of the alleged sale to Wilmot."

"A search of the manufacturer's website for the jet engines revealed they are valued at around USD9mn (approximately GBP4.8mn each) - considerably below the GBP25mn which Wilmot claimed to have sold them (for)."

The tax authority continued: "The Heroi Stakhorskyi departed Southampton docks on 12 December 2006 but the ship manifest recorded its cargo as New crop beans but no engines. The ship was bound for the Black Sea via Gibraltar, Malta, Egypt and Turkey not the Iraqi port of Umm Quasr."

Wilmot claimed he arranged the deal through an Iraqi national, Mr Al Majari of Basra and that he found a supplier by visiting a trade fair in Excel in London, and that he had arranged to inspect the engines in a London warehouse.

A search of Wilmot's office, where he had been living, in Temple Chambers, Temple Avenue, London, uncovered a laptop computer which was forensically examined and found to have been used in the creation of the purchase and sales invoices, export documents and contracts.

Wilmot explained this by saying that he had scanned the invoices when he received them, but forensic examination was used to discredit this argument.

Wilmot had pleaded not guilty to VAT fraud.