London | Former British prime minister Tony Blair has urged the West not to stop intervening in countries at risk from Islamic extremism, even after his controversial support for the US invasion of Iraq in 2003 left an enduring scar on his Labour Party and his legacy.

Twenty years after the September 11 attacks in the US, he said Islamic terrorism remained “a first-order security threat”, including the growing risk that terrorists could potentially launch “bioterror” attacks such as releasing viruses.