[Spoilers] Beth Bailey/Sophia Myles

[Tea Lady]

If you haven't read this already, this is what the BBC Spooks website says about the character of Beth:

"Beth is illiberal but principled and not at all establishment. She's opinionated and a provocateur who never plays by the rules. She joined M.I.5 when she was young and was trained by them, but was kicked out due to her inability to follow orders. Harry was the officer who made that decision. He saw how volatile she could be and that she wasn't mature enough to be a spy. Her reputation in the field is what attract M.I.5 to Beth. She wants to go back and agrees to because of her own agenda."

I am not sure I realised it was Harry who decided to kick her out. Maybe that was why he didn't instantly give her another chance when she saved his life, because she'd had her second chance already with Harry.