The Queen, visiting France on Thursday, has created problems for diplomatic officials with her hat collection.
With many of the world's most renowned leaders sporting distinctive hats (even William Hague) we wonder if it's high time David Cameron got one for himself...
Obama's baseball cap
The US President's love for the Chicago White Sox is always on show with his trusty black cap.
In most shots of Barack Obama away from the White House, at the gym or on holiday, he will almost certainly be wearing it.
Castro's patrol cap
Military headwear became synonymous with the Cuban revolutionary at the peak of his powers.
The hat stressed Fidel Castro's connection with the armed forces and turned him into a soldier rather than a politician.
Pictures emerged just last week of Kim Jong-un, the North Korean dictator, sporting a summery look as he walked around a construction site in Pyongyang with an open tunic and straw boater.
The Russian President was photographed on a hunting trip last summer wearing a camoflaged slouch hat, complete with tassels.
You would have to think the Nigerian President has watched Indiana Jones a few times.
Goodluck Jonathan may not do himself too many favours in inspiring trust, given the fedora's association with gangsters.
The President of Liberia likes to wear a traditional headdress and flowing robes. Ellen Johnson Sirleaf is known as the 'Iron Lady' to her supporters and was joint winner of the Nobel Peace Prize in 2011.