Whilst it is true to say that Berties break through role was as tyranical headmistress Agatha Trunchbull in the Royal Shakespear Companys 'Matilda' for which he won an Olivier award in 2012, he has a very impressive record of theatre work in his biography and has won regular crittical acclaim.
Perhaps his most noteable performance was as Leo Frank in Jason Robert Browns original London production of the musical 'Parade' in 2007 fo which he was nominated for an Olivier.
Here are some photos from past productions:
The Man of Mode
Corum Boy edit
Damned By Despair
Matilda Stratford Upon Avon
The Hairy Ape