Colin Powell, the US Secretary of State, has revealed his personal involvement in the fight against Aids, describing in an interview to be broadcast today how he and his wife Alma help to educate young girls in Washington about sexual abstinence. Mr Powell drew on his personal experience to defend plans to spend one third of the $15bn (£8.8bn) the US has pledged to the global fight against Aids on abstinence projects. Mr Powell also repeated his view that Aids was a matter of "national security" and "more than a health problem". He was interviewed by the BBC World Service...