I think Ratter is right. This would take an enormous amount of resources. How many cameras and recorders would it take to cover every street in the UK? When the suspect passed from one camera to another, where would be the continuity to prove that the next camera was following the same person? Many crimes are committed over the weekend and are not discovered until the business opens on Monday. The recordings would take longer than that to view. They cannot be sped up because of the small time interval concerned, and often have to be rewound to check something.