There is also deep concern about the seeming breakdown of relations between Downing Street and the civil service with the resignation of Jonathan Jones, the head of the government’s legal department, in protest at the government’s actions seen as the latest example of this development.

Lord Butler, who was head of the civil service for 10 years, said he had never encountered anything as “difficult” as the current turmoil during his time as cabinet secretary and warned that the government had undermined the UK on the international stage.

Boris Johnson has put forward only “weak” arguments to support the changes he wants to make to the EU withdrawal agreement, Lord Butler added.

Former officials have also expressed disquiet at constant attacks on the judiciary, media and others who challenge the government, in what is seen as emulating the practices of the Trump administration in the US.

The consternation about what is happening from those who have served the country comes as the prime minister faces a growing rebellion from Conservative MPs and peers to the proposed legislation which overrides key parts of the EU withdrawal agreement, with a former minister, Bob Neill, trying to organize a parliamentary veto.

There is also rising criticism of the British government’s conduct among European politicians and officials. The EU has already warned that it may take legal action if the British government went ahead with its breach of the treaty.

The assessment of the damage the government is doing to the UK is damning. It has been pointed out that this country has repeatedly criticized states like Russia and China for breaking the “rules-based international order” and yet now holds that it is perfectly justified to breach international law.

Asked by The Independent whether civil servants had been put in a difficult position by the government, Lord Butler said: “Yes, well I think it might, (Jonathan) Jones felt so strongly about it that he felt he had to resign his position. That’s as it were a moral decision on his part, but that’s a different thing from a breach of the civil service code.”

When pressed if he had dealt with anything comparable during his decade-long tenure as cabinet secretary, he replied: “No, I didn’t experience something as difficult as this. There were things that ministers decided to do, or governments decided to do which I didn’t agree with, but I never had anything which I thought was so morally repugnant that I had to resign. Nor was I asked to do something that was illegal. So no, I think this is a particularly difficult issue.”

The former civil service chief added: “They have put forward a justification for it. It’s only a contingent thing: if they can’t get an agreement and the EU act in such a way that the government considers that its obligations under the Good Friday Agreement are breached – that’s their defense. A lot of people think it isn’t a good defense and I think that’s why the government will have a lot of difficulty putting this bill through parliament.

“I think it is very difficult to justify breaking a recently agreed international agreement, the Northern Ireland Protocol – I think their argument is weak. You can say if they thought this was a contingency, they should have thought of it before they agreed the protocol.”

General Sir Richard Barrons, the former chief of Joint Forces Command who served in Afghanistan, Iraq and Northern Ireland, told The Independent that “what the government is proposing is short-sighted tactics which will do much harm strategically in the wider world. In fact what is being done is particularly stupid.

“It will undermine us with our enemies by giving them the opportunity to accuse us of hypocrisy when we call them out for breaking the rules-based international order. It will also undermine us with our allies who will doubt whether they can rely on us to keep to an agreement, keep to our word.”

General Barrons continued: “The UK can be accused of being like Russia, which breaks international rule but then pretends it hasn’t, or China, which is trying to change the actual rules. China may be big enough to do this, but I am afraid the UK is not.

“We are a middle ranking power and part of the influence we have is dependent on cooperation with allies and is spread through international laws which we have signed up to and we have actively promoted since the Second World War.”

He also spoke about growing concern about the fractious relationship between Downing Street and the civil service. “The resignation of the treasury solicitor is yet another example of am emblematic problem between this government and the civil service, this is obviously a serious ongoing situation”, Sir Richard said.

Former diplomat John Ashton, whose posts have included being special representative for climate change, said: “I hope that the bomb that has been placed in the withdrawal bill won’t actually go off, either because we reach a deal with the EU including on the Northern Ireland Protocol, or because the offending clauses get removed from the bill as it goes through parliament.

“But if the government does what it threatens to do, that would be catastrophic for our reputation in the world, and for our ability to secure our national interests. Our friends would weep; our enemies would laugh.

“In that event we would be telling everyone that no promise we make from now on will be worth the paper it is written on. With the rules-based system already under attack from elsewhere, including the current US administration, we would be putting ourselves on the side of the attackers, not those defending it, with whom our real interest lies.”

Ashton, who had also run an environmental think tank, pointed out that the UK was co-hosting a major international conference on climate change, COP26, next year.

“This will be the most significant international gathering since the pandemic (which led to its postponement). It will be crucial not only in moving the regime of obligations and promises forward to deal with the existential threat of climate change, but more widely in rebuilding confidence, post-pandemic, that we have it in us to respond successfully through cooperation to all the great global challenges we now face.

“At COP26, we will be saying to the world: we must all redouble the promises we have made to each other on climate change, and we must reaffirm our trust in each other that we will keep our promises. If we can’t do that the COP will be a failure.

“What message will it send to everyone else if the host country has itself blithely, unilaterally and for reasons of short-term expediency walked away from its binding international obligations in another area?”

Sir William Patey, who served as British ambassador to Afghanistan, Iraq, Saudi Arabia and Sudan, told The Independent: “The withdrawal agreement contains the mechanism to address disputes, as all major agreements do. The government could make use of these if it can show that the EU was acting in bad faith. One can also, of course, pull out of an agreement at the end of the day.

“But what this government is doing is keeping the agreement and then just taking out the bits which they don’t like. This is breaking international law: their own lawyers are saying its breaking international law.

“This will have severe consequences. Never mind Britain’s reputation, this will be very, very bad practically, weakening Britain’s position in agreements and alliances, including future ones on trade and security, while giving adversaries the excuse to accuse us of hypocrisy.”

Sir William continued: “We are also seeing some very worrying developments, both in America and over here. There seem to pretty regular attacks by some in government on people we need to hold those in power to account; institutions which are important for a healthy democracy like the media, neutral public servants, the judiciary.”

Sir Simon Fraser, the former head of the Foreign Office, accused the government of trying to jettison some of the most significant parts of the withdrawal agreement. He said: “It is a very significant disapplication of important parts of that agreement.

“The fact they are saying they are doing this because they signed the agreement in a hurry and didn’t realize the implications is hardly a convincing argument.”

In an incendiary article on Saturday, the prime minister doubled down on his intention to introduce the legislation next week in the Commons and in an attempt to dissuade potential rebels from scuppering his plans, claimed the EU could “carve up our country” unless MPs pass the Bill.

“I have to say that we never seriously believed that the EU would be willing to use a treaty, negotiated in good faith, to blockade one part of the UK, to cut it off, or that they would actually threaten to destroy the economic and territorial integrity of the UK,” he wrote in the Daily Telegraph.

And in a broadcast round, Michael Gove, the Cabinet Office minister who held emergency talks with EU officials earlier this week over the government’s plans, echoed Johnson’s comments and claimed ministers’ actions were “entirely consistent with the rule of law”.

He added: “We’re doing our part – generously – to help protect the EU’s own single market, but we’re clear that what we can’t have even as we’re doing all that is the EU disrupting and putting at threat the integrity of the United Kingdom.

“These steps are a safety net, they’re a long-stop in the event, which I don’t believe will come about but we do need to be ready for, that the EU follow through on what some have said they might do, which is in effect to separate Northern Ireland from the rest of the United Kingdom.”

Some Tories, however, remained unconvinced and Tobias Ellwood, the senior Conservative MP who chairs the Commons defense committee, said on Saturday that “unamended I cannot support this bill”.

“Already this bill is damaging brand UK, diminishing our role-model status as defender of global standards. As we go to the wire, let’s see more British statecraft – less Nixonian Madman Theory,” he tweeted.

Writing in Saturday’s Daily Telegraph newspaper, Johnson said the EU’s stance justified his government’s introduction of new legislation to rewrite its Brexit withdrawal treaty — a bill that is causing deep alarm among his own MPs.

Talks between London and Brussels on a future trading relationship are deadlocked as both sides struggle to prize apart nearly 50 years of economic integration, after British voters opted for a divorce.

Absent a deal by the end of this year, when the full force of Brexit kicks in, Johnson said the EU was bent on an “extreme interpretation” of rules for Northern Ireland.

“We are being told that the EU will not only impose tariffs on goods moving from Great Britain to Northern Ireland, but that they might actually stop the transport of food products from GB to NI,” he wrote, AFP reported.

“I have to say that we never seriously believed that the EU would be willing to use a treaty, negotiated in good faith, to blockade one part of the UK, to cut it off, or that they would actually threaten to destroy the economic and territorial integrity of the UK.”

The EU has threatened Britain with legal action unless it withdraws the contentious legislation by the end of September, and leaders in the European Parliament on Friday threatened to veto any trade pact if London violates its promises.

Johnson’s accusation drew scorn from Luis Garicano, a Spanish member of the European Parliament.

“I think it’s pretty ridiculous. I think Mr. Johnson insists on having his cake and eating it,” he told BBC radio on Saturday, noting that the treaty’s protocol on Northern Ireland was plain to see when the prime minister signed it in January.

The government’s claim that the treaty contains unforeseen problems was also undercut by a Financial Times report Saturday that British civil servants explicitly highlighted the potential issues in January, at least a week before Johnson signed it.

Under the EU withdrawal treaty, Northern Ireland will enjoy a special status to ensure no return of a border with EU member Ireland, in line with a 1998 peace pact that ended three decades of bloodshed.

The food dispute centres on the EU’s refusal so far to grant Britain “third country” status, which acknowledges that nations meet basic requirements to export their foodstuffs to Europe.

The EU is worried that post-Brexit Britain could undermine its own food standards, as well as rules on state aid for companies, and infiltrate its single market via Northern Ireland.

After another difficult round of trade talks this week in London, chief EU negotiator Michel Barnier said “many uncertainties” remained about Britain’s food export regime after January 1.

“More clarity is needed for the EU to do the assessment for the third-country listing of the UK,” he said in a statement, ahead of another round of talks next week in Brussels.

Johnson said his government remained committed to finding agreement with the EU by the end of the year.

“But we cannot leave the theoretical power to carve up our country -– to divide it -– in the hands of an international organization,” he wrote, calling the new UK Internal Market Bill a “legal safety net”.

The prime minister’s article appeared after he held a chaotic videoconference on Friday evening with mutinous Conservative MPs who are aghast at the prospect of the government tearing up an international treaty.

Senior Conservative backbencher Robert Neill was unimpressed by Johnson’s calls to push the bill through and prevent a renewal of the Brexit infighting that paralyzed parliament last year.

“I believe it is potentially a harmful act for this country, it would damage our reputation and I think it will make it harder to strike trade deals going forward,” Neill told Channel 4 News.

The government crowed at one breakthrough Friday in clinching its first post-Brexit trade pact, with Japan. But critics noted it would boost Britain’s long-term economic output by just 0.07 percent, and that trade with the EU is far higher.

Three years have been wasted failing to agree what Britain wants from its negotiations, the Institute for Government finds – handing the advantage to countries on the other side of the table.

It means the controversy over the US demand to sell its chlorinated chicken – which has stalled a deal with Washington – will be repeated, its report concludes.

The think tank criticizes the “unforced error” of launching into complex trade talks before ministers have decided what they want their post-Brexit regulations to be.

“Three years ago, we warned that the government had not set up the necessary structures for effective decision making on key trade policy issues,” said Maddy Thimont Jack, a senior researcher, The Independent reported.

“The government did not heed that warning then, but it now needs to move urgently to put them in place. Otherwise, it will find itself losing control of trade and regulatory policy to better-prepared partners.”

The criticism comes as trade talks with the EU remain deadlocked because the government cannot agree with its future state aid rules and needs to satisfy Brussels’ fears of undercutting.

Hopes of a deal with the US this year have been abandoned – and even a revamped deal with Japan has run into trouble, in a row over access for UK agricultural products.

Notoriously, Brexit-backing Conservatives claimed it would be easy to strike numerous lucrative deals with other countries, once the UK was free to negotiate alone.

“The only thing we have to fear is fear itself,” Johnson said before the 2016 referendum. “I think there is a huge opportunity. Do free trade deals, belief in ourselves.”

In fact, a deal with the US, even if it can be struck, would add only 0.2 percent to GDP in the long run, the Treasury has estimated – and a continued deal with Tokyo only 0.07 percent.

The IfG study, Trade, and Regulation after Brexit, says it will be impossible to marry the desire for a clutch of new agreements and for “regulatory autonomy” – because a weakened UK will be told to change its standards in return.

It warns ministers that the UK:

Could “easily fall victim” to other nations “threatening to collapse the talks if they do not get what they want”.

Will be “vulnerable to challenge” at the World Trade Organization, if its currently dysfunctional dispute system becomes operational again.

Has failed to agree its stance on key regulatory issues, which risks it being “pushed into making concessions it shouldn’t”.

Risks damaging the union unless it can reach an agreement with the other UK nations, which are responsible for implementing trade deals and “could choose not to.”

His comments follow a study earlier this month which warned that Britain risks a second wave of COVID-19 this winter twice as large as the initial outbreak if schools reopening happens without an improved test-and-trace system.

Writing in the Mail on Sunday, Johnson said reopening schools in September was a national priority. Schools would be the last places to close in future local lockdowns, he was quoted by another newspaper as telling a meeting on Thursday.

Schools in England closed in March during a national lockdown, except for the children of key workers, and reopened in June for a small number of pupils.

The government wants all pupils to return to school by early September in what Johnson has called a “national priority”.

“Keeping our schools closed a moment longer than absolutely necessary is socially intolerable, economically unsustainable and morally indefensible,” Johnson wrote, Reuters reported.

The economic costs for parents who cannot work if schools are shut are spiraling, and the country faces big problems if children miss out on education, the prime minister warned.

“This pandemic isn’t over, and the last thing any of us can afford to do becomes complacent. But now that we know enough to reopen schools to all pupils safely, we have a moral duty to do so,” he wrote.

The Sunday Times newspaper reported that he has ordered a public relations campaign to ensure schools open on time and told the meeting last week that they should be the last places to close behind restaurants, pubs, and shops.

Johnson added that authorities are getting better at identifying and isolating local outbreaks, but said it was important that the power to order national action was held in reserve, Sky News reported.

He told The Sunday Telegraph: “I can’t abandon that tool any more than I would abandon a nuclear deterrent.

“But it is like a nuclear deterrent, I certainly don’t want to use it, and nor do I think we will be in that position again.”

Johnson’s comments could lead to further tensions between ministers and their scientific experts after Sir Patrick Vallance, the government’s chief scientific adviser, warned on Friday there was “a risk” that national measures could be needed as winter approaches.

Announcing a further easing of England’s lockdown restrictions on Friday, Johnson said he hoped there could be a “significant return to normality” in time for Christmas.

He also said the government had given local authorities new powers to close specific premises, shut outdoor spaces and cancel events to control outbreaks.

Johnson told the Telegraph: “It’s not just that we’re getting much better at spotting the disease and isolating it locally, but we understand far more which groups it affects, how it works, how it’s transmitted, so the possibility of different types of segmentation, of enhanced shielding for particular groups, is now there.

“We’re genuinely able now to look at what’s happening in much closer to real-time, to isolate outbreaks and to address them on the spot, and to work with local authorities to contain the problem locally and regionally if we have to.”

Johnson, who was pictured with his baby son Wilfred for the first time on Saturday, insisted his agenda for domestic reform and “leveling up” the economy would not be blown off course by the pandemic as he approaches his first anniversary of being in office.

He said: “We want to be a transformative government because there’s a massive opportunity in this country to do things differently and to do things better.

“We’ve seen that really exemplified in what happened with coronavirus.”

The prime minister’s comments came as Scotland recorded its highest daily positive COVID-19 tests for almost a month.

Scottish government figures show there were 21 confirmed results over a 24-hour period as of 2 pm on Saturday.

It is the highest number since June 21 when there were 26 positive test results.

Deputy first minister John Sweeney warned the public of the ongoing threat of coronavirus, with the surge in positive cases coming after lockdown measures were eased on Wednesday.

He tweeted: “Thankfully another day of no deaths recorded due to #COVID. 21 positive cases however remind us of the danger still out there.”

The data also shows there were no deaths involving someone who had been confirmed as having COVID-19, meaning the death toll under this measurement remains unchanged from Thursday at 2,491.

A total of 18,422 people have now tested positive for the virus in Scotland.

There are 305 people in hospital with confirmed COVID-19, a decrease of 11 from Friday.

Of these patients, three are in intensive care – which is the same as the previous day – however, five other people are in intensive care with suspected coronavirus.