I was chatting with one of my colleagues at work last night. He's a Muslim originating from the Pashtun region (which covers north west Pakistan and a sizable chunk of Afghanistan), although I believe that he himself was born in the UK. We talked about the 5 British troops and 3 Afghanis killed by the Afghani security officer. My colleague said that this event was because the Afghani people don't see the Taliban as the enemy, they see the UK and US security forces as the enemy, and that the Afghani people see only 2 ways to win, military victory or death. I then asked if he was saying that the only mutually satisfactory outcome would be to just wipe out the entire population of Afghanistan (NB, I'm not actually proposing we do that), perhaps start by dropping Napalm on all the population centres. He agreed (after I'd explained what Napalm is and what it does) that that would be the only possible outcome.
Based on conversations I've had with other people, including recent immigrants from Afghanistan, I don't actually think that he is correct.