During his Presidency, Barack Obama only ever broke security protocol for one person, Queen Elizabeth II on her ninetieth birthday.

Royal biographer Robert Hardman revealed the extraordinary story on the first episode of a new season of the Daily Mail’s Queens, Kings and Dastardly Things podcast.

Alongside co-host Kate Williams, Hardman looked ahead to Trump’s upcoming second state visit while exploring other famous diplomatic encounters between British royalty and US presidents.

One of the most memorable of these encounters happened in 2016, when Obama was making his farewell trip to Europe and specifically timed his visit to Britain to be the first world leader to wish the Queen a happy 90th birthday.

Hearing this, the Queen’s reaction was typically straightforward – she and Prince Philip would simply ‘pop out’ and collect the Obamas in a Range Rover when their helicopter landed at Windsor.

The President’s Secret Service detail were having none of it however, sparking what Hardman called a ‘very serious row’ with the Palace.

He said: ‘The Secret Service said absolutely no way is that happening. The President can only be driven around by us.

During his Presidency, Barack Obama only ever broke security protocol for one person, Queen Elizabeth II on her 90th birthday

The Queen’s reaction was typically straightforward – she and Prince Philip would simply ‘pop out’ and collect the Obamas in a Range Rover when their helicopter landed at Windsor

The President’s Secret Service detail were having none of it however, sparking what Hardman called a ‘very serious row’ with the PalaceThis created a real ding dong. I spoke to the US staff that had organised the trip and they said there was a very serious row over which car they were going to go in and who was going to drive it.

‘This dilemma went right the way up to Obama himself, who had to decide. He thought, well it obviously means quite a lot to them, so I’ll go in their car.

‘Obama flew in and for the only time in his entire presidency, he and the First Lady were driven, not in a bullet-proof, bomb-proof whatever, but in a Range Rover driven by Prince Philip.

‘Obama and the Queen were in the back, Philip was at the wheel and Michelle was in the front – and off they went, tootling around the Park.’

Obama later wrote about the incident in his memoirs, recalling how the Queen casually told him ‘I’m sure there’s some rule about who sits where, but sit wherever you like.’

‘It was very cordial and friendly’, Hardman told the podcast.

‘By that point, the Obamas and the Queen and Prince Philip had seen a lot of each other throughout his presidency.

‘There was real rapport there by that point.’

Alongside co-host Kate Williams, Hardman looked ahead to Trump’s upcoming second state visit while exploring other diplomatic encounters between British royalty and US presidents

Hardman said Trump’s upcoming meeting with King Charles should be equally warm, noting they’ve already met several times and ‘get on very well’

Robert Hardman: ‘Trump and Charles get on very well. There will be an element of – nice to see you again Mr President’

Hardman said Trump’s upcoming meeting with King Charles should be equally warm, noting they’ve already met several times and ‘get on very well’.

Trump’s most recent meeting with a member of the Royal Family was Prince William at the 2024 reopening of Notre Dame Cathedral in Paris.

The royal biographer said: ‘Trump and Charles get on very well. There will be an element of – nice to see you again Mr President.

‘Nonetheless, it’s still a huge deal for both sides.’