In my statement earlier today, I said that the Police and Security services needed to investigate whether or not Abidi was acting alone. Those investigations continue, but the work undertaken throughout the day has revealed that it is a possibility we cannot ignore that there is a wider group of individuals linked to this attack.
It is now concluded, on the basis of today's investigations that the threat level should be increased for the time being from severe to critical. This means that their assessment is not only that an attack remains highly likely, but that a further attack may be imminent. The change in the threat level means that there will be additional resources and support made available to the police as they work to keep us all safe.
I ask everybody to be vigilant. The terrorists will never win and we will prevail.