The head of the British Foreign Office says the invasion of Afghanistan has made the world safer.
Sir Peter Ricketts told Radio New Zealand National's Sunday programme that denying Al Qaeda a safe haven in Afghanistan has reduced its capacity to operate.
Western forces entered Afghanistan after the 9/11 attacks on New York in 2001 were planned from there. Al Qaeda were hosted by the Taliban who were overthrown.
Sir Peter said that without doing this, the West would be facing a worse threat now, but added that the job there is not yet done.
In addition, he said that the "worrying spread" of Islamic extremism was also a worry in Pakistan and the West needed to work closely with the Pakistan government to gain control over lawless tribal areas there.