HMRC chief Jon Thompson its £has defended 20bn estimate of the costs for the companies in the post-British EU-exit customs system favored by leading Brexiteers.
He told deputies that a technology-based system called “max fac-solution” – would cost the company a similar amount to the EU to leave with no deal.
Mr Thompson said the high frequency of transactions meant that the company would still have to fill out customs declarations.
The Prime Minister wants to exit the UK leave the EU customs Union post-British EU.
Mr Thompson said that the HMRC had calculated the cost on a bottom-up approach, the views of the cost for each transaction.
How did HMRC get to cost £20bn inch?
Technology-based customs system ‘costs could be £20bn’
In a letter to the Committee Chairman, Nicky Morgan, he explained that HMRC were the calculations based on the current EU trade data and the VAT data and current customs declarations.
He said that the combination of the volume of additional declarations and their costs would produce an estimated additional burden on the British side of the border, of around £6.5 billion per year.
Mr Thompson added that there would be additional costs on the EU, because the UK-export declarations, would be declarations need to be complemented by EU-import-and Vice versa.
These figures produces a total cost for UK-EU trade in goods over £17-£20bn a year, he said.
The Committee also heard from the heads of the ports of Calais and Zeebrugge, the convinced seemed to be that if a politician could decide what they wanted, that it could be delivered, until the end of December 2020, when the transitional period is due to end.