Sir Nigel Irvine in The Fourth Protocol and Francis Urquhart in House of Cards were almost the same character. Powers behind the scenes. Guys who knew what was really going on. The big difference was Francis Urquhart became corrupted by his pursuit of power. In the first episode he would have been happy to have been given a cabinet position. By the end - he wanted it all and was willing to justify any means (and I do mean any) to accomplish his goals. Sir Nigel Irvine was content in just helping to avoid nuclear holocaust.
I also have to admit that I am fascinated by the British Parliamentary system. Their politics are just very cool to observe makes watching our C-SPAN like - well like watching C-SPAN.
What is funny is that Netflix is producing a re-make of the series starring Kevin Spacey and to be directed by David Fincher. It will be an Americanized version based in DC not London. I'll probably tune into that but if you haven't watched the original - do yourself a favor and download it.