Queen Elizabeth has worked with 14 Prime Ministers, including holding confidential weekly meetings. It is not known whether she has influenced her Prime Ministers, or what happens when they clash.

"I was there to photograph her meeting the new prime minister but for me ... and Ms Barlow said the Queen "greeted her with a big smile". The photo of the Queen shaking hands with Ms Truss sparked ...

In “Queen Victoria and Her Prime Ministers,” Anne Somerset insightfully describes the arc of Victoria’s reign by tracking what amounted to a shifting variety of governing partnerships.

Earlier in his trip, Trump attended a NATO summit in Belgium before flying to Britain to meet with Prime Minister Theresa May and have tea with Queen Elizabeth II. Follow Trump’s journey here ...