This weekend, British Prime Minister David Cameron delivered the most important speech of his premiership so far. His address to the Munich Security Conference was a powerful condemnation of a deadly Islamist ideology that threatens the very fabric of British society, as well as a wholehearted rejection of “the doctrine of state multiculturalism.” All the more remarkable, this bold speech came amid a suffocating culture of political correctness in the United Kingdom, which has frequently stifled open debate during the past two decades.

The British government has identified Islamist extremism as the number one threat to national security. Cameron was absolutely right to point out that “the biggest threat that we face comes from terrorist attacks… we have got to get to the root of the problem, and we need to be absolutely clear on where the origins of these terrorist attacks lie. That is the existence of an ideology, Islamist extremism.”

It is easy to see why these remarks were necessary. In 2009 British intelligence services revealed that there are 2,000 extremists involved in Islamist terrorist plots in the UK, with many more providing backing. MI6, the UK’s foreign intelligence agency, has since warned of a new wave of suicide bomb attacks by home-grown terrorists, with mounting fears over the radicalization of British Muslims.

In his speech Cameron called for an end to the self-imposed cultural segregation of some Muslim communities, calling on all Britons to adopt “a clear sense of shared national identity that is open to everyone.” He also made it clear that the days of engagement by the British government with extremist Islamic groups that claim to be moderate are over. This is a clear, and welcome, break with the lax policies of his Labour predecessors.

Prime Minister Cameron’s words in Munich were a huge step in the right direction. His government now needs to put them into action to ensure that the Islamist terrorist threat is emphatically defeated, both at home and abroad. That includes a commitment to winning the war in Afghanistan, and ensuring the Taliban do not retake power, as well as a determination to isolate the extremists at home, and crush the Al Qaeda networks that proliferate across the UK.

Nile Gardiner is Director of the Margaret Thatcher Center for Freedom at The Heritage Foundation.