When a beaming President Obama shook hands with Pope Benedict XVI for the first time in July, he was the latest in a long line of world leaders to seek an audience with the pontiff.

“It’s a great honour,” Obama said as he greeted the Pope, thanking him for their meeting at Vatican City. As he left he added, “We look forward to a very strong relationship between our two countries.”

Prince Charles met the Holy Father in April last year, on his first visit to the Vatican since he and Princess Diana met Pope John Paul II in 1985. He and the Duchess Of Cornwall exchanged gifts with him and Charles was “touched” by the Pope’s presents of an honorary medal and a drawing of St Peter’s Basilica. In return, Charles gave the Pope plates with paintings of plants from Highgrove.

In June 2006, Tony Blair had a private audience for more than half-an-hour with Benedict in the pontiff’s Vatican study. Downing Street said they “talked about the challenges of globalisation and the importance of dialogue between the faiths to battle extremism and terrorism”.

Gordon Brown and his family met the Pope at the Vatican in February 2009. The Holy See said they had a “cordial” talk about the financial crisis and “initiatives benefiting less developed countries”.

Gaffe-prone former President George W Bush was true to form when he greeted the Pope in 2008 with,“Your Eminence, you’re looking good” – a title reserved for cardinals – instead of “Your Holiness”.

But Benedict also meets ordinary people who need his prayers. Soon after Madeleine McCann vanished in Portugal in May 2007, he met her parents Kate and Gerry, and blessed a photo of their missing child.