The Prime Minister added: "It is important that those engaged in terrorism realise that our determination to defend our values and our way of life is greater than their determination to cause death and destruction to innocent people in a desire to impose extremism on the world."
The Queen, who hosted a banquet at Gleneagles last night but was said to be back at Windsor Castle, said in a statement: "The dreadful events in London this morning have deeply shocked us all. I know I speak for the whole nation in expressing my sympathy to all those affected and the relatives of the killed and injured. I have nothing but admiration for the emergency services as they go about their work."