In the second part of Who's Watching You? Richard Bilton continues to explore the hidden world of surveillance.

He meets those who have made our private lives their business, including former soldiers watching suspected workplace thieves, corporate spooks trawling companies' rubbish for lucrative secrets and suppliers in the booming trade in tracking devices, secret cameras and hidden microphones.

And Richard also delves in to the criminal underworld of hackers and blaggers who steal and sell our information.

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

The three part series Who's Watching You continues Monday 1 June, 2009 at 2100 BST on BBC Two. Or catch up on iPlayer afterwards.