The prime minister’s political judgement has been criticised after a meeting between King Charles and the leader of the European Union was cancelled.
European Commission president Ursula von der Leyen had been expected to travel to Britain on Saturday amid speculation a deal to fix issues with the Northern Ireland Protocol is near.
The German politician was also due to meet the King at Windsor Castle, Sky News said.
There were talks about calling a potential protocol pact the “Windsor Agreement” after a meeting with Charles, the broadcaster said.
UK government sources confirmed Ms von der Leyen’s trip was called off but it is likely Downing Street and Buckingham Palace worked together on the reported arrangements.
Rishi Sunak’s critics said the scheduled meeting brought into question his handling of the protocol negotiations.
Jacob Rees-Mogg, a former business secretary and senior member of the Tory Eurosceptic European Research Group (ERG), told The Independent: “(The government) would not normally call upon the sovereign to advance a particular policy aim that is controversial within British politics. So I think it’s very much on the borderline of constitutional propriety.”
Mr Sunak is keen to secure the backing of not only his Tory MPs but also the Democratic Unionist Party (DUP) for any protocol reform as he looks to restore powersharing in Belfast.
The DUP is refusing to take part in Stormont’s cross-community devolved government in protest at the impact the Brexit treaty is having on trade between Northern Ireland and Great Britain.
Former DUP deputy leader Lord Dodds said meeting Ms von der Leyen would have politicised the monarch, and argued the reports “reinforce the questions about No 10’s political judgment over the protocol”.
Sammy Wilson, a DUP MP, said any Windsor rendezvous with the EU leader would have been “a cynical use” of the King’s position and seen in Unionist circles as the sovereign endorsing the deal.
He branded the prime minister “naive” and accused him of “dragging the King into a hugely controversial political issue”.“The only conclusion we can come to is he knows that in these negotiations he hasn’t achieved the objectives he set out for himself and his own party,” Mr Wilson said on Sky News of Mr Sunak.
“Nor has he achieved the promises that he had made to ourselves and was now trying to get the King to pull the thing over the line for him.”
Baroness Hoey, a Northern Irish Brexit supporter and former Labour MP, said any such meeting would have been “outrageous”.
UK government sources said that, while Ms von der Leyen’s trip was no longer going ahead, it would not have been improper for the King, as head of state, to meet a visiting European leader.
“It would be wrong to suggest the King would be involved in anything remotely political,” a Government source told PA.
Buckingham Palace would not comment.
Labour’s shadow Northern Ireland secretary Peter Kyle said Downing Street should have realised utilising the King would have “constitutional implications” and been “highly insensitive to the politics of Northern Ireland”.
“It certainly is nothing we should be involving His Majesty in,” he told Sky.
No 10 said Mr Sunak will be spending the weekend speaking to “relevant stakeholders” as he looks to get a protocol deal over the line.
Downing Street said “intensive negotiations” with Brussels are still taking place.
Multiple reports suggest the deal between the UK and the EU is all but done – with Mr Sunak delaying an announcement until he is confident it will be accepted.
The protocol, signed by former prime minister Boris Johnson in 2020, was designed to prevent a hard border with Ireland after Brexit by effectively keeping Northern Ireland in the EU’s single market.
But the treaty has incensed unionists due to the trade barriers it created between Northern Ireland and the rest of the United Kingdom.
According to The Times, the current offer on the table would mean an overhauled protocol, which would remove almost all checks and most paperwork on goods crossing the Irish Sea.
The newspaper said the agreement would also mean control over the rate of VAT and state aid policy will fall to Westminster rather than Brussels for the first time since Brexit was enacted.
Speculation that No 10 is preparing to confirm a deal to fix the protocol intensified on Friday after a Downing Street source said “good progress” was made during a phone call between the prime minister and the commission president.
Any announcement of a deal is expected to set up a possible clash with Conservative Brexit hardliners, with the prime minister promising MPs will be given the chance to “express” their views on the new terms.
The DUP has issued seven tests to win its backing for any deal, including addressing what it calls the “democratic deficit” of Northern Ireland being subject to EU rules while not having a say on them.
