The prime minister is “an English nationalist” – not a Conservative – who has turned his back on traditions of standing up for the Union and international co-operation, the former Tory party chairman said.
“What we’re seeing is Boris Johnson on this runaway train of English exceptionalism and heaven knows where it is going to take us in the end,” Lord Patten said.
“I want the best for my country, I fear for what’s happening at the moment and I fear for our reputation around the world, I fear for what will happen economically.
“I hope that I’m wrong to feel so depressed about the outlook but I don’t think that Mr Johnson is a Conservative, I think he is an English nationalist.
“And all the things that Conservatives used to believe in – like standing up for the Union, like not attacking our institutions, like the judges, like believing in international co-operation – seem to have gone out of the window.”
Tobias Ellwood, the Conservative chair of the Commons defence committee condemned the “absolutely irresponsible” sabre-rattling, as prospects for a Brexit agreement fade.
Michel Barnier, the EU chief negotiator, and his UK counterpart David Frost have until only Sunday to somehow bridge the divide between the two sides.
Then, Mr Johnson and Ursula von der Leyen, the European Commission president, will speak again – and pull stumps on the negotiations if they believe there is no prospect of them succeeding.
Lord Patten, speaking to BBC Radio 4 added: “I do fear for the worst because it is very, very difficult to see what the plan is, how we’re going to do so brilliantly when we’re out of this ‘cage’ of Europe – which we of course helped to build because the main constructor of the single market was Margaret Thatcher.”
Meanwhile, large retailers could cut back on shipping to Northern Ireland if the Brexit paperwork triggers the feared huge delays, hauliers are warning.
Martin Reid, the Road Haulage Association’s (RHA) director for Scotland and Northern Ireland, said it is “crazy” that industries are still in the dark about the nature of customs checks.
Shellfish caught in the Highlands may even have to be dumped if they cannot be taken to a crucial market in France on time, he said.
On Friday, the prime minister claimed a no-deal Brexit would be “wonderful” as the EU agreed it was now the most likely outcome.