Hywel Bennett stars as Martin Durnley, a rich but damaged Oxford University drop-out with a hatred of his banker stepfather, played by Frank Finlay. His mum babies the boy, a consequence of Martin's elder brother, a Down Syndrome sufferer (or 'Mongoloid' - or even 'mentally backward' as they say here), being in full-time care, and the doctors having warned Martin's parents not to have any more children - just to be on the safe side. Too late: troubled mummy's boy Martin, with his cuddly toys and penchant for smashing his own reflection, appears to have proved the doctors misgivings.
