Unlike Beale, he has tried his hand at outright villainy, scoring an enormous hit as the original Javert in Les Miserable. But instead of capitalising on that popular success, he quickly left the musical to return to the RSC where he has played Trigorin in The Seagull, Brutus in Julius Caesar and Benedick in Much Ado About Nothing.

In Jekyll and Hyde, Allam has a harder task than Beale, portraying a soul in torment wrestling with a side of himself that he both loves and is appalled by.

Allam's upbringing as a minister's son may be of some assistance in finding a key to the role. He is impressed by Edgar's (the director) decision to employ two actors. "I actually can't imagine doing it any other way; the bonus is that you get some very compelling scenes between Jekyll and Hyde describing what is going on in his head. There is a danger that audiences will forget that the two actors are playing one person but we've done various things to try and get round that. I've played some of Simon's scenes and he has played certain of mine. A lot of people have pointed out that Simon and I look completely different but in fact in the book Hyde is described as being much smaller and darker".

The Strange Case of Dr Jekyll and Mr Hyde is not a traditional Christmas show, suitable for only the most mature children. Allam believes that the great thing about it is that they don't have to try and rouse interest in the story. "Go up to anybody in the street and they may not have read the book but almost everybody will have heard the story". True enough, but that also means that onlookers will be waiting to see whether Edgar can produce something distinctly theatrical to match the tension of the best films and the extraordinary atmospherics of Stevenson's writing.