Professor Simon Wessely from King's College London is a leading expert on mental health problems in the military.
Every year in Afghanistan we're going to create more cases of post-traumatic stress disorder. The other worry is when this is over what will happen if society doesn't see it [the operation in Afghanistan] as something we're proud of or successful in? People start to think, was it all worth it... what did we achieve?
You can hear more from Professor Simon Wessely on today's ITV News at 1:30.