Britannia, so the song went, ruled the waves, and for more than a century, much of the planet - in 1922 that was 458 million people, and 33,670000 square kilometres, one quarter of the world's population and total land mass.

But since World War II, the United Kingdom has been in terminal decline. 
 
Today, Britain is a fifth rate military power, and a fifth rate economic force, a country that cannot even win at sports it invented - see cricket, rugby and tennis.

And yet London still decides the fate of 16 overseas territories, with a grand total of 230-odd-thousand people, who still claim to be members of the British Commonwealth.

But Britain also helped decide the fate of millions of Iraqis when Tony Blair, the then British prime minister, unilaterally decided to back George Bush, the then US president, in his illegal invasion.
 
So what gives this faded island off the coast of Europe the right to act like a global power player? What is so great about Great Britain?

This episode of Empire can be seen from Wednesday, May 26, at the following times GMT: Wednesday: 1900; Thursday: 0300, 1400; Friday: 0600; Saturday: 1900; Sunday: 0300.