- Zoe's departure from the show in Series 3.
- Danny's death in the Series 3 finale.
- Fiona's death in Series 4 was a tearjerker that carried on for episode after episode, as we also saw Adam's ongoing grief, fear for Wes, and struggle to tell Wes that his mother is dead.
- On that same note, Adam's death in the Series 7 premiere. He dies right after being reunited with Ros, another character who was forced to be Put on a Bus, and a character who clearly wanted to be in a relationship with him. Every single character was openly upset over his death, and to drive it all home, the episode ends with Harry telling Wes (who is now an orphan at this point) that his father's dead while he was waiting for him at a soccer game.
- Colin's death in the Series 5 premiere, especially because it looked like he was going to Face Death with Dignity, only to break down begging for his life when he realizes he's about to be brutally hanged from a tree.
- Even if she was an unlikeable woman, Maya's death is pretty upsetting due to Lucas' reaction to it. Even if Lucas was evil, he lost the one person he blatantly said was more important than his job and his own life. It's no surprise that the poor bastard wound up killing himself shortly afterwards.
- Lucas North is a walking Tear Jerker once you find out his backstory. He bombed a British embassy that killed seventeen people, and then strangled the real Lucas North to death so he could steal his passport and join MI-5. He then spent fifteen years (eight of which were in prison) trying to forget about his awful crimes, only for Vaughn to show up and convince him to do evil deeds again. And then Vaughn made him realize with great horror that he was Evil All Along, and just pretending to be a good guy. In the last episode he's in, Lucas is so traumatized over everything (including the death of his true love, Maya) that's happened to him, and the people he's betrayed or killed, that he throws himself off a building.
- The series finale. Especially the last ten minutes.
Tear Jerker / Spooks