On 18 August The Sunday Times published a leaked document relating to Operation Yellowhammer. This was the Cabinet Office’s planning assumptions to respond in the short-term to a no-deal Brexit. The Sunday Times said the leaked document outlined the short-term impact to the UK of no deal. It said the impact would be severe.
It said fuel would become less available and 2,000 jobs would be lost if the government counteracted this by setting petrol import tariffs at 0 per cent. Medical supplies would be vulnerable to “severe extended delays.” Freight disruption at ports could last for three months, before traffic flow settled at 50-70 percent of the current rate. Passengers would get stuck at EU airports, the Channel Tunnel and Dover. There would be protests, and possibly also a rise in public disorder and community tensions. Fresh food would become more expensive and less available. Perhaps worst of all, the document said a hard border would return in Ireland after plans to avoid widespread customs checks collapsed.
The leak was highly embarrassing for Boris Johnson, who had earlier claimed that a no-deal Brexit would bring no more than “bumps in the road.”
Michael Gove, the minister in charge of preparations for no deal, immediately tweeted that “Yellowhammer is a worst case scenario.” Later in the day, he strengthened the claim in front of television cameras, saying Yellowhammer represented “absolutely the worst case in the event of a no-deal Brexit.”
Other senior government figures repeated the claim. Speaking to Sky News on 18 August, Energy Minister Kwasi Kwarteng went even further, saying there was “a lot of scaremongering around and a lot of people are playing into Project Fear and all the rest of it.”
Two days later, Conservative Party Chairman James Cleverly told ITV’s Good Morning Britain that the document “is not a prediction… It’s a set of worst-case scenarios.”
However, Rosamund Urwin, the reporter to whom the document had been leaked, insisted that its heading had said “Base Scenario,” as was stated in The Sunday Times. She tweeted a screenshot from the paper, which had printed a version of the document. Urwin received important backing from the former head of the British civil service, Bob Kerslake, who in a letter to The Sunday Times the following week explained the meaning of “base” scenario:
The government has argued that this is not an assessment of what might actually happen but a “very worst case” scenario. The difficulty with this argument is that the document is a “base-case” assessment.
As anyone experienced in government knows, the base case is the expected case drawn from assumptions of what is most likely to happen. It stands between the best, most optimistic, scenario and the worst possible outcome.
The tone and content of the report makes this clear — it was written as an internal document and sets out the arguments in an informed, measured and realistic way.
If anything, the document underestimates the risks, because it says little about the impact of the public’s quite understandable actions to protect their own interests. Nor does it set out the serious risks to the UK economy from a no-deal Brexit.
Two weeks later, Gove appeared to retract his claim that the Yellowhammer document referred to a “base scenario” when he appeared before parliament’s select committee for exiting the EU. Asked by chair Hillary Benn if the document contained the term “base case” or “base scenario,” Gove at first said no. But he later used the term. When Benn asked him to clarify whether the words “base scenario” appeared in the document, Gove said they had.
“So you are correcting what you said earlier,” Benn said. “Absolutely,” replied Gove.
Final confirmation that the document had related to a base scenario for a no-deal Brexit came when MPs forced the government to publish the Yellowhammer document in full on 11 September. Journalists noted that the document appeared to be identical to that which had been leaked to The Sunday Times. Urwin said it was identical. The only difference, she said, was that the heading had been changed from “Base Scenario” to “Reasonable Worst Case Planning Assumptions” and a section on fuel had been redacted. Although it has not been confirmed, the suggestion was that in the time between the leak and the publication of the document in full the government had changed the title to reflect its claim that Yellowhammer related only to the worst case scenario. In the days after its publication, Gove repeated his claim that Yellowhammer related to the worst-case scenario.
I have told the story of the government’s response to The Sunday Times leak in great detail because it goes to the heart of the deceit practised by the Johnson government over the economic consequences of Brexit. There has been no serious denial of The Sunday Times story, while the reporter, Rosamund Urwin, has stood her ground. If she is right, Gove repeatedly misled the media — and consequently the British people — about the status of the Yellowhammer document. It is reasonable to speculate that he was doing this in order to play down the severe risks of a no-deal Brexit. Conservative Party Chairman James Cleverly and Energy Minister Kwasi Kwarteng repeated the falsehoods uttered by Gove. Further evidence emerged when the Yellowhammer document was published on 11 September. And Scottish First Minister Nicola Sturgeon told the Scottish Parliament the next day “the only difference” between the published version and the version her government had received was the title. “The version we have has the title base scenario,” she said.