A former Brexit planning chief has warned “everybody should be worried” about the consequences of the UK leaving the EU without a deal.
Philip Rycroft was the most senior civil servant in the department for exiting the European Union (DExEU) until he resigned in March.
Rycroft said more than 16,000 civil servants had been scrambled to work on Brexit-related issues in a BBC Panorama interview to be broadcast on Monday night.
Speaking for the first time since his resignation, he called a no-deal Brexit “fraught with risk,” and called Britain’s current situation “unprecedented.”
"I think everybody should be worried about what happens in a no-deal situation. We would be taking a step into the unknown,” he said.
He said getting a deal with the EU was the “rational outcome” over the next few months for both sides.
The scale of preparations made it "the biggest exercise across government over the last few decades," but he said good preparations by officials could not prevent no-deal Brexit having significant consequences.
“That is a very major change and it would be a very abrupt change to our major trading relationship," he added.
The stark message is the latest in a string of warnings about the potentially devastating consequences of a no-deal Brexit for the British economy.
Both Boris Johnson and Jeremy Hunt, the two remaining candidates in the race to lead the Conservative party and become the next prime minister, have not ruled out leaving the EU without a deal.
Another former top civil servant, the UK’s former Brexit border chief at HMRC, said last week that no-deal preparations in March felt like “preparing for a crisis.”
Karen Wheeler said at a think tank event that Calais, Dover and Folkestone could be “clogged up” with lorries after a potential no-deal Brexit soon after the UK’s scheduled departure on 31 October.
She said the sudden changes to Britain’s terms of trade with Europe could mean new checks at borders and delays.
Many experts have previously warned the scale of the rupture to Britain’s biggest trading partner could cause significant upheaval, from shortages and price hikes for essential goods to security concerns, a plummeting pound and a steep decline in foreign investment.
The president of the National Farmers Union said on Sunday no-deal could be “economically disastrous” for agriculture.
She warned food imported from abroad that would be illegal to produce in the UK and farms could forced out of business because of the new trade rules that would come into effect once Britain was outside the bloc.
A representative of chartered accountants in the UK also said last month that the disruption and negative consequences could cause a “flurry of profit warnings” by major firms reliant on the EU for trade.
Such profit warnings could trigger a “systemic loss of confidence” on the markets that could hurt the UK economy as a whole, according to Martin Manuzi, European director of the Institute of Chartered Accountants.