But she clearly has a more mischievous, adventurous side, as evidenced in her sassy turn in Trumbo or her action-comedy series RED. Now she's adding war movies to her repertoire with the drone-strike thriller Eye in the Sky.

Helen Mirren plays a Colonel in the film

In the film, she plays Colonel Katherine Powell, a British officer in command of a top-secret mission using drones to capture terrorists in East Africa. The character was written for a man, but director Gavin Hood (Ender's Game) immediately saw Mirren in the role.

And Mirren responded to the script's authenticity. "I think it was well researched," she says. "So in many ways it's a true story, or maybe an invention of a true story."

The role also challenged her to explore a new kind of character. "I had to learn military speak," she laughs. "But more important was who this person would be, far from my experience and my knowledge. I would be hopeless in the military, absolutely useless! So I had to get my head around someone who wanted to become a military person in the first place and then was good at it enough to bring her to become commander. And to be a woman in that situation means she had to be a particularly strong-willed and dedicated person."

Mirren was also fascinated by equipment that can operate a drone from halfway around the world. "In knowing how far this technology has taken us, I realised that it's going to take us a lot further," she says. "It's very interesting to look at human invention and imagination, the extraordinary ability to create things medically and in warfare. But at what point do you make a moral and philosophical judgement, that we can do this but we're not going to because it's wrong? As to a certain extent we have done with the atom bomb. We could, we've got it, but it's wrong, so we will try and shut it away."

And she hopes her character will stir the debate. "Many people will come out of the cinema saying, 'I don't think she should have done that. I don't think that was right,'" Mirren says. "That's what we want people to do, actually, to discuss the issues afterwards, because we are all complicit in these decisions. These decisions are made on our behalf."

Watch the trailer for Eye In The Sky: