The US president was granted the rare honour of addressing both Houses of Parliament today, an opportunity he used to speak of the US’s and the UK’s shared values.

Despite the special relationship between the two countries sometimes being “over-analysed” for signs of strain, Obama affirmed its enduring strength.

“I have come here to reaffirm one of the oldest and one of the strongest alliances the world has ever known,” he said.

“The reason for this close friendship doesn’t just have to do with our shared history, our shared heritage, our ties of language and culture, or even the strong partnership between our governments.

“Our relationship is special because of values and beliefs that have united our people through the ages.”

Pointing to the unrest in the Arab world, Obama said Arabs were “longing for the same freedoms we take for granted”.

“There are few nations that speak louder for freedom than the US and the UK,” he said.

“There’s no doubt that the US and the UK stand on the side of those who want this.

“Now we must consider how we can back up those words with deeds, starting with Tunisia and Egypt.”

In a press conference with Prime Minister David Cameron earlier today, Obama said that the relationship between the US and the UK is “stronger than it has ever been”.

Obama is the first US president to address the nation’s leaders in Westminster Hall. He joins only a few select figures to have been granted the same privilege, including Nelson Mandela, Charles de Gaulle and the Pope.

The audience included MPs and peers from all parties, as well as former prime ministers Gordon Brown, Tony Blair and Sir John Major.

Yesterday, the president and his wife Michelle lay a wreath at the Grave of the Unknown Warrior in Westminster Abbey.

They were greeted by the Dean of Westminster, the Very Rev Dr John Hall, who imparted something of the abbey’s significance, including its central role in the nation’s history as the setting for the coronation of every King and Queen of England since the crowning of William I in 1066.

“Here every day thousands of people from all over the world including very many from the United States are welcomed as visitors and pilgrims,” said Dr Hall.

Obama caused a slight stir by signing the wrong date in the abbey's guestbook, despite apparently asking the dean what date it was.

He wrote in the guestbook: "It is a great privilege to commemorate our common heritage and common sacrifice."

The message is undersigned by Obama and Michelle but appears to be dated "24 May 2008".