Meet C, the higher spec Jackson Lamb

It's a long, long walk from Jackson Lamb to Blaise Metreweli. Longer than the road from a raddled ruin of a hasbeen spycatcher to the impeccable poise of a fitness fanatic spy chief, from a rat-infested Victorian firetrap in London's Liverpool Street to the gleaming postmodern block in Vauxhall Cross.

- Bernard Gray

Yet, for all that, the fictional star of Slow Horses and the very real new chief of MI6 have some things in common. A fierce intelligence, a determination to protect their people, a competitive instinct to win. Both also have dual natures of, and yet not of, the tribes they have made their own. Lamb is run down, cast out, cynical, but a lifelong counterintelligence loyalist. Metreweli is from British establishment central casting: Cheltenham Ladies' College, Westminster School, Cambridge rowing blue. She is also the daughter of a Ukrainian émigré, who fled the bloody battleground of the eastern front in the wake of the second world war.

As Jackson Lamb returns to our screens for a new outing this week, Metreweli is settling into her new office as C, the head of MI6. Of the two, it's a fair bet that Metreweli faces the more difficult task.