Thomas Bladen is an agent with MI-5.
Technically he is but he is specialty is surveillance so if you normally saw Bladen out in the field on an operation, it would be him watching the bad guy. If you were the bad guy, smile nicely for the camera because Bladen is pretty good at his job and if you are the assignment, he has you covered.
That is on the positive side of the Bladen ledger. On the other side is the fact that his boss at the department is his ex-girl friend. Actually maybe closer to his boss's boss since his new immediate boss is the guy that she left Bladen for so that does make for an interesting situation at work.
Luckily for Bladen he will soon have a whole of worse things to concentrate on, like people trying to kill him, which he is against, and people trying to kill innocent people while he is watching which he is also against though not quite as much.