The EU's former chief negotiator, Michel Barnier, has said Britain's supply chain crisis was a “direct consequence” of Brexit.
Speaking in London, Mr Barnier said the UK's decision to rebuild non-tariff barriers and ending freedom of movement for European workers had added to the current economic crisis across the UK.
Britain is currently facing a shortage of 10,000 lorry drivers, leading to bare shelves in some British supermarkets, with many blaming Brexit for the disruption.
Fears of shortages have also led to panic buying by motorists at some British petrol stations in recent days, despite assurances from the government that there was enough fuel.
At a London School of Economics event, Mr Barnier claimed there was a “clear link” between the UK's driver shortage and the decision to end freedom of movement.
He said the implementation of non-tariff barriers between the two trade blocs had added to the economic crisis.
“It is a direct and mechanical consequence of Brexit,” he said.
However, Mr Barnier admitted that the effects of the pandemic and the surging cost of energy prices and raw goods were being felt across the continent.
There is “no single answer” to solve the crisis, he said.
Mr Barnier made the comments on Monday as he promoted his new book, titled My Secret Brexit Diary, which details his time on the European Commission's Brexit negotiation task force, which he led from 2019 to 2021.
In the book, Mr Barnier accuses British politicians of being “unprepared” for negotiations with the bloc and implied that his counterpart David Davis did not know the difference between the single market and the customs union.
During Monday's talk, Mr Barnier ruled out a proposal by MEP Guy Verhofsadt to enact an “associate” EU citizenship for British workers in Europe who have been stripped of residency rights.
He said that Britain was a third country and must be treated as such.
“UK citizens have lost their rights because of Brexit, nothing else,” he added.
The 70-year-old, who is planning to run for the French presidency, professed to have a long-standing respect for Britain and said he had voted to admit the country into the European Economic Community during a referendum in 1971.
He said that he would welcome Britain back as an EU member if the general public voted to do so.
“The door is open. My answer is very clear. It is the sovereign choice of the British people.”