Chaudry Ali of Middlesex was found guilty and jailed for nine years in 2012 for spearheading the fraud, which used two couriers who would fly to Dubai, via Frankfurt, to collect large amounts of gold jewellery.

The couriers would leave the UK in the afternoon, arriving in Dubai early the next morning. They would collect the gold then leave Dubai the same evening returning to Frankfurt, and meet Ali in an airside lounge. They would then swap bags – Ali leaving with the gold and the courier leaving with a bag of clothes.

Both Ali and his courier would take separate flights back to the UK, passing through the EU entry channel at UK arrivals. In case he was stopped by officers, Ali carried forged paperwork which claimed he was a legitimate VAT-registered gold trader who had travelled to Europe with the gold in his bag. As he had not left the EU then no duty would be payable on the gold.

An HMRC investigation found that this ruse had been used on over 200 flights.

Kevin Newe, assistant of criminal investigation, for HMRC, said: ‘Ali believed he had found the perfect fraud that was beyond detection, but he was wrong.

'Our investigators uncovered the fraud and in addition to his current prison term he will have to spend an extra ten years in jail unless he repays crime profits of over £4.3m within the next four months.

'Our work doesn’t stop with sentencing – we will pursue criminal profits to reclaim them for the taxpayer and the UK economy.’