Speaking to The Mirror, Armitage revealed that the programme's cast miss the actress while filming on set.
"We really miss Hermione," he admitted. "She was a very calming influence and I loved her humour."
The actor, who plays Lucas North, also confessed that he is unsure of his own future with the show.
He explained: "I’ve said to the producers, ‘Over to you. You decide’. If that means sending Lucas to Manchester or severing his head, I don’t know. Or I could end up in the deep fat fryer. They’d owe me a brilliant exit."
Armitage also promised that the true nature of his character will finally be revealed.
"Basically, Lucas isn’t who you think he is. It’s always been hovering there, whether or not he’s a double agent," he said.
The ninth series of Spooks is due to air in the autumn.