|MI-5 is called Spooks in the UK
My favorite is Inspector George Gently, with two partners made of an aging detective (who remains dignified and sober even when he's furious) and his annoying young sidekick (who should be shot purely for his irritating habits, but they're just so darned polite they keep him on). This is a fairly new series but it's set in Durham County in the early 1960's, and they have done something with the lighting that it almost looks black and white with James Bond-style music and retro clothing and cars. Martin Shaw and Lee Ingleby are the stars and the writing is crisp and the detectives are flawed but compelling.
Another recent development is I've become hooked on audiobooks again. A Visit from the Goon Squad by Jennifer Egan is a wonderful book, and having it read dramatically while I clean house or work on beading jewelry is kind of cool. I'm also listening to Thomas Hardy's Tess of the D'Urberville's (read by George Gently star Martin Shaw) at night to relax before bed. The Tiger's Wife by Tea Orbecht and Hardy's Return of the Native (read by Alan Rickman) are next in line. There's something very peaceful about hearing a quiet voice reading aloud. Years ago I had a lengthy project where I listened to John Le Carre's The Constant Gardener as I worked. Today when I drive by and see the finished project I start remembering the story...they are cemented together.
If you're up for trying an audio book, Audible and E-Music both offer free trials. You can also download an audio book right off Amazon to your MP3 player or PC.