We have watched terrorist attacks on foreign shores in recent years with horror, praying it would not be us.

This time, it was.

A suspected terrorist took innocent lives - innocent bystanders on Westminster Bridge and a policeman bravely doing his job.

We can't even begin to comprehend what the families and friends of those whose lives were cruelly taken in the attack will be feeling.

Our thoughts and condolences are with them.

And our heartfelt gratitude goes to the policemen and women whose professionalism stopped this attack from being any worse than it was.

The hundreds of people who work in parliament, keeping the cogs of our democracy turning, were in safest possible hands when terror struck in the heart of London.

We know other attempts to take innocent lives have been thwarted.

This one got through. But we must not be cowered.

Stories of MPs, strangers and colleagues all stepping in to help each other were not just an illustration of the greatness of humanity at difficult times.

They were a demonstration of defiance to terrorists who wish to divide us.

We must go on as we have before.

And we do so in the knowledge that we have brave police officers who serve us on the frontline to protect us.