sarah atiq, bbc news, torkham, on the pakistan—afghanistan border.ns, mps from all sides have criticised the prime minister for the government's role in afghanistan. the former prime minister theresa may said it was �*incomprehensible' that the uk was not doing more to maintain a presence, and mps who've served in the armed forces spoke up for veterans who fought there and who now question what it was all for. but borisjohnson argued that nato's "core mission" in afghanistan had succeeded. here's our political correspondent ben wright. prime minister, have you let down afghanistan? _ a statement was written, the explanation prepared — borisjohnson headed to parliament, brought back from its summer break. prime minister! the chamber was crammed, shoulder—to—shoulder now restrictions are lifted. the sacrifice in afghanistan is seared into our national consciousness, with 150,000 people serving there from across the length and breadth of the united kingdom. no matter how grim the lessons of the past, the future is not yet written. and at this bleak turn