British Spy Movie Ends with a Large Fire

Around 2010, give or take, I saw a movie (or possibly a single season, few-episode, mini-series) on one of my movie channels on Dish TV. It took place in the UK (and/or possibly Ireland). The story centered around two, male, middle-aged spies.

The scene that really stands out in my mind is one of the spies was conducting surveillance on something across the street. On the second floor of a flat, far from a window, he placed a table atop another table and climbed up onto it. He had a sniper rifle with a scope on it, and used that to watch something across the street. Because the table was far from the window and light didn't penetrate that far into the room, no one outside could see him on the table, so he didn't have to be worried about being seen behind the rifle. I don't recall that he ever fired the rifle, just looked through the scope.

There were some other spy things going on, like the two guys broke into a family's house and placed bugs in the telephones, because they were surveilling the wife. One of the two spies had a second household or apartment under a false name in Ireland (I think, otherwise the countryside of the UK). He would go to it periodically to maintain his cover story and false identity and was planning to quietly retire there when he quit the spy business.

I believe the movie ended with a large fire. I think it was in the apartment the spy was planning to retire in. He may have died in that fire.

Please help me identify this movie (or mini-series.) Thank you.