Sir Mark Brydon (played by Jason Isaacs)

Sir Mark Brydon is Her Majesty's Ambassador to the United States of America. A career diplomat, he has served extensively in the Middle East. He was a special envoy to the Central Asian Republic of Tyrgyztan in the '90s and the former foreign adviser to the British Prime Minister. Due to his achievements, he's been rewarded with the plum job in the British diplomatic service.

Brydon is an out-of-the-box thinker, calm under pressure, and very knowledgeable about global politics. He doesn't rely on the naïve assumption there is a special friendship between the UK and the US. He knows that the British only have clout when they have something to offer. The fact that he is unmarried, unusual for the UK Ambassador in Washington, has fueled the rumor mills. He often has to fight off the attention of wealthy divorcées.

Jason Isaacs has already had experience in an American political series, playing Colin Ayres on The West Wing. Highly regarded as a character actor, he's also known for portraying Michael Caffee on the series, Brotherhood, Lucius Malfoy in the Harry Potter movies, and Col. Tavington in The Patriot.