Former US president Barack Obama has said getting to know the Queen was among the “great privileges” of his time in office, as he paid tribute to the “steadfast” monarch on her Platinum Jubilee.

He said the sovereign, now 96, reminded him a little of his grandmother when they met, and he liked to think they had formed a “special relationship” of their own over the years – making reference to the phrase often used to characterise the alliance between the US and UK.

Mr Obama, who served as the 44th US president from 2009 to 2017, said he and wife Michelle had not known what to expect on his first trip to Buckingham Palace, but they “shouldn’t have been worried”.

Your life has been a gift not just to the United Kingdom, but to the world

In a video message broadcast by the BBC, he said: “When you’re President of the United States you meet a lot of remarkable people, and you try under all circumstances to maintain your composure.

“But that’s harder than you think when you’re visiting Her Majesty.”

Mr Obama added: “Before I took office, Michelle and I hadn’t been to too many palaces, so we weren’t sure what to expect on our first trip to Buckingham.

“But we shouldn’t have been worried. Her Majesty put us at ease with her grace and generosity.

“So much so that I walked away thinking she actually reminded me a little bit of my grandmother.

“And in the years since, I’d like to think Her Majesty and I have formed a special relationship of our own.”

Mr Obama said getting to know the monarch was “one of the great privileges of my years in office”, and he learned “so much” from her example.

He said it would be an “understatement” to say the world had changed slightly in the 70 years since she took the throne, but stressed her character “never has”.

“Your steadfast stewardship of one of our most important democracies has made the world safer and more prosperous through war and peace, times of adversity and times of prosperity,” he added.

“Your life has been a gift not just to the United Kingdom, but to the world. And it is with gratitude for your leadership and the kindness that you’ve shown me and my family that I say may the light of your crown continue to reign supreme.”