Only education, and correct law enforcement in the UK can stop the use of heroin or opiates.
Spraying agent orange around the Helmand valley will just help us lose the battle quicker, and cause more deaths amongst the UK contingent.
A stark question but which is worth more: someone prepared to put their life on the line for their country, or someone who despite knowing it will ultimately kill them, can't say no to a pusher?
The whole counter narcotics issue is a govt justification red herring. It could happen in the future, but there is a whole lot of stuff that needs to happen first.