In the final part of his series investigating how the UK has become one of the most watched places in the world, Richard Bilton tries an exercise that is used to train surveillance officers.

For more information about surveillance visit the Who's Watching You website.

The three part series Who's Watching You? concludes on Monday 8 June, 2009 at 2100 BST on BBC Two. Or catch up with episodes one and two anytime on BBC iPlayer