I was devastated to see that Canada, a long-standing and important friend of the United Kingdom and member of the Commonwealth, was attacked this week by a convert to Islamic extremism.

I said a few months ago, when action against Isis in Iraq and Syria was being mooted, that the most important security concern that Britain faces is homegrown terror, and those returning from abroad, resettling in the UK, having been radicalised and trained by Islamic extremists. This remains, to me, our foremost security threat.

Despite being involved in our wars against foreign tyrants and terrorists, Canada has often been considered one of the safest places in the Western world.

Unassuming and beautiful, Canada holds a special place in the hearts of most Britons. To see her under attack is deeply saddening.

And despite how evident it now is that what happened on the streets of Ottawa could just as easily happen on the streets of London, I fear we are still paying more attention to people thousands of miles away rather than to preventing escalation of the terror threat at home.

As a nation, our priority must shift to the dozens, if not hundreds of homegrown Islamists that we are beginning to learn are dead set on harming our country and our people on our streets.

I sincerely hope that Ottawans and Canadians in general are able to rely on Britain for any support they may need at this difficult time. It is no stretch to say that an attack on a Commonwealth partner is an attack on the Commonwealth as a whole.