The Queen’s weekly audience with the Prime Minister was postponed this week to allow Boris Johnson to focus on the race against the clock to secure a post-Brexit trade agreement.
Mr Johnson usually telephones the monarch each Wednesday evening to update her on Government matters, but there is no record of this week’s audience in the Court Circular.
Buckingham Palace said the Queen will speak with the PM next week.
Mr Johnson travelled to Brussels for a three-hour dinner with European Commission president Ursula von der Leyen on Wednesday.
A Palace spokesman said: “The audience was postponed due to the Prime Minister’s busy diary. One is planned for next week.”
The Queen’s audiences with the PM are traditionally face-to-face encounters, but arrangements have been altered in recent months because of the coronavirus crisis.
When the Queen moved to Windsor Castle for her safety ahead of the first lockdown in March, the monarch and Mr Johnson began holding the conversations over the phone.
Although the monarch remains politically neutral on all matters, she is able to “advise and warn” her ministers – including her PM – when necessary, according to the royal family’s official website.
Secret plans to evacuate the Queen and other senior royals from London were reportedly previously drawn up in case a no-deal Brexit triggered rioting on the streets.
In February 2019, The Sunday Times said Whitehall was formulating emergency proposals which had been repurposed from those originally formulated during the Cold War in the event of a nuclear attack by the Soviet Union.
But that was before the pandemic of 2020 took hold and the Queen decamped from Buckingham Palace to the safety of Windsor in lockdown.
They are preparing for a quiet Christmas together without the rest of the royals.
It will be the first time the Queen, 94, and 99-year-old Philip have spent the festive period at Windsor, rather than heading to Sandringham in Norfolk, in more than 30 years, in a bid to keep them safe during the Covid-19 crisis.
The monarch was dragged into a constitutional row during her summer holiday in August 2019 amid Westminster’s bitter Brexit battles when Mr Johnson asked her to suspend Parliament for more than a month.
The sovereign was duty bound to hold a Privy Council meeting at Balmoral, her private Scottish estate, where, acting on the advice of the PM, she approved an order to temporarily close – or prorogue – Parliament for five weeks.
Opposition leaders wrote to the Queen in protest and then Commons speaker John Bercow said the move was a “constitutional outrage” designed to stop Parliament debating Brexit.
In the end, the Supreme Court ruled Mr Johnson’s advice to the Queen to suspend Parliament was unlawful because it had the effect of frustrating Parliament.
During the 2017 State Opening of Parliament, the Queen’s speech, written by the government, laid out the Brexit legislation that the government intended to pass during the parliamentary session.
Some suggested that the monarch’s hat, which was blue with yellow floral details, resembled the EU flag.
“It was a coincidence but, boy, did it attract a lot of attention, and it certainly made us smile,” she wrote in her memoirs.
Although the Queen remains politically neutral, commentators saw her words in 2019 as a nod to the toxic mood of the public debate around Britain leaving the EU.
In a speech to mark the centenary of the Sandringham Women’s Institute (WI), she spoke in favour of individuals seeking “common ground” and “never losing sight of the bigger picture” in what was interpreted as a veiled reference to Brexit.
In 2019, she acknowledged the “bumpy” path her family and the country had experienced during the past 12 months.
She said the Christmas message of peace and goodwill was a reminder of what can be achieved when people abandon their differences and “come together in the spirit of friendship and reconciliation”.
During a state visit by King Willem-Alexander of the Netherlands in October 2018, the Queen spoke publicly about Brexit for the first time, telling the king that “as we look toward a new partnership with Europe” the values shared by the UK and the Netherlands “are our greatest assets”.
The Queen’s focus in 2020 so far has been the Covid-19 crisis.
Such unprecedented times saw the monarch make not one but two rare televised addresses to the nation, telling a troubled country in lockdown: “We will meet again.”
During the referendum campaign in 2016, a major row broke out over a front page story that stated the Queen supported EU withdrawal.
The Sun’s report said an anonymous source had told the paper she had voiced strong Eurosceptic views during a lunch in 2011 with the then-deputy prime minister Nick Clegg.
The former Liberal Democrat leader later said the suggestion the Queen had given him a “tongue lashing” about Europe was “preposterous”.
Buckingham Palace complained to the press watchdog Ipso over the “Queen backs Brexit” front page.
Ipso later upheld the complaint and ruled the headline was inaccurate, although The Sun stood by its article.