the return of an old face

[loladom]

Not so sure Spooks would have the budget for either of the above two popular choices, given how many other new characters are joining. That theory also puts to bed another person I thought of

Series 10 Spoiler: show

Jules Silver. But he's way too high profile now.

So I'll stick to my above ideas of Mace, Juliet or Tessa even though the Jenny A is/was a big name, she hasn't been in anything for ages that I recall (please correct me) so maybe she just wants to do something?

Alternatively, a more educated guess is now pointing towards Malcolm. He of course knew Harry so well and perhaps may arrive to defend him in his hour of need. Right, I've talked myself into Malcolm. Can the summer go quick enough