Every year nearly two million people in the UK are victims of domestic abuse, with police receiving 100 calls an hour about domestic violence. But what is being done to tackle the violent men at the root of the problem? More and more abusers are getting access to courses and therapies designed to help them change their violent behaviour. At stake is the safety of children and partners.But at a time when women's refuges are closing due to lack of funding this is a highly controversial approach, which some even say is dangerous. With extraordinary access to some of these courses, Panorama asks how effective these interventions are and if violent men can ever really change.