AS a regular member of the Spooks crew Geoffrey Streatfield got himself into some sticky situations.
But few of the TV scenarios faced by cocky Calum Reed were potentially as devastating as the secret his scientist is suspected to be carrying in his mind in the at-times gripping Copenhagen.
Currently enjoying its final week at the Lyceum as part of Sheffield Theatres’ Michael Frayn season, Geoffrey is Werner Heisenberg, a man thought to have been capable of creating the ultimate bomb at the twilight of the Second World War.
Based around a real life meeting between his fellow physicist and mentor Nils Bohr and Bohr’s wife Margrethe, Copenhagen leaps back to a crucial time in human history when science had the potential to change the course of mankind in the most destructive fashion.
“Misunderstood is the most accurate word, a compromised figure whose actions have never been fully explained,” says Geoffrey when asked to describe his man, just returned from Germany to Denmark when the crucial meeting takes place.
“He stayed in Nazi Germany and ran the atomic bomb project and therefore a lot of the scientific community turned their back on him. On one level that was a conscious choice, to stay in order to make sure Hitler didn’t get a bomb, which seems to me quite an admirable thing to have achieved.
“Frayn gives him a very fair hearing, to understand that morality is not as black and white as perhaps we would like it to be.
“There’s no question he’s not a Nazi. He didn’t join, he was called a white Jew because of his defence of Jewish physics and interrogated by the Gestapo. He must have turned a blind eye to things that were going on.
“I would hope someone watching this play would think there’s a greater humanity in this person than you might think initially and that we should all stop as the play does and take several looks at something before judging it as it appears to be.
“It wasn’t one heroic act of ‘I will not make a bomb but I will stay and pretend to’, because also he did bad maths: he got the calculation wrong which actually spared him having to make the choice.”
While the audience is left to a large extent to form a verdict about Heisenberg, Geoffrey is keen to project the positive things about his character.
Either way, at least it is not as cut and dried as his time in Midsomer Murders. “I was a triple killer and I’m still in jail,” says the actor, who used to visit cousins in Sheffield as a child.
“Apparently it’s bad to be a killer, because you can’t go back.”
Copenhagen concludes on Saturday.