He first played Othello in 1997, when the role was still synonymous with white thespians 'blacking up'. Now, nearly three decades on, he, Chiwetel Ejiofor and other Black actors discuss how best to tackle Shakespeare's formidable tragedy "I had no intention of playing this character again. But as soon as the light went on, the house caught fire " and it's been burning ever since." David Harewood is talking about Othe…