Following the announcement, Ben Stephenson (Controller, BBC Drama Commissioning) promised a “fittingly high octane thrilling finale” for the spy drama.

Writing on Twitter, Sam Vincent revealed: “[It would be] unthinkable to let it drag on, peter out, and get cancelled, ending on an unresolved cliffhanger…”

The writer added: “We haven’t known all way through that this was [definitely] the end. But: we have known long enough to create a hopefully fitting finale… I’ve seen a cut of the last ep. Obviously, I’m all kinds of biased, but… well. Can hardly wait for you to see it!”

Vincent also thanked fans for their support: “Thanks for all your messages (and howls of grief). It’s sad of course, but absolutely the right decision to have a proper end.”

Set to begin on BBC One next month, the spy drama’s final series will feature new cast members Lara Pulver (True Blood), Geoffrey Streatfeild (Ashes To Ashes), Alice Krige (Deadwood) and Jonathan Hyde (Titanic), alongside returning characters Harry (Peter Firth), Ruth (Nicola Walker), Dimitri (Max Brown) and Tariq (Shazad Latif).

> Buy the Series 9 boxset on Amazon.

Watch the BBC’s recent ‘Original British Drama’ trailer, featuring footage from Series 10…