‘Do not resuscitate’ orders – who decides?

A County Antrim man has spoken of how he was unaware that a "do not resuscitate" (DNR) order had been placed on his medical file. He feels his human rights have been violated. Earlier this year, a study by the Royal College of Physicians in England found one in five families was not consulted when doctors had decided not to revive their relative. So what are the rules? Who should decide?