A drug which appears to erase painful memories has been developed by scientists.
The astonishing treatment could help sufferers of post-traumatic stress disorder and those whose lives are plagued by hurtful recurrent memories.
But British experts said the breakthrough raises disturbing ethical questions about what makes us human.
They also warned it could have damaging psychological consequences, preventing those who take it from learning from their mistakes.
Dr Daniel Sokol, a lecturer in medical ethics at St George's, University of London, said: 'Removing bad memories is not like removing a wart or a mole. It will change our personal identity since who we are is linked to our memories.