Yet secret filming has shown the message in some hospitals is not getting through.

The investigation features two years worth of secret filming by Ghanaian journalist Anas Anas.

Last Monday, BBC's Panorama aired a programme that featured secret filming from inside the same warehouse.

The Panorama report used secret filming to track the supply chain of dogs into and around Britain.

Using secret filming they have uncovered some shocking truths about where and how these animals are being bred.

Owners of the Ohio farm were charged with animal cruelty following six weeks of secret filming of events there.

This report contains secret filming.

He and the 10 other defendants were originally detained after secret filming by the BBC's Panorama at Winterbourne View, near Bristol.

Chris Buckler reports on the popularity of the drug, and - using secret filming - shows how easily it can be bought for personal use.

Using secret filming, he met up with an underground network charging migrants as much as £1,500 to hide them in lorries destined for mainland Europe.

Secret filming for the BBC has revealed chaos in one of the biggest prisons in England and Wales.

Secret filming by BBC's Panorama has uncovered poor standards of care at one of England's largest care homes.

Secret filming by Panorama discovered that some factories hide the long hours from retailers by keeping two sets of books.

Secret filming obtained by the BBC offers a rare glimpse of Raqqa, the last stronghold for the so-called Islamic State in Syria.

I googled secret filmings and read court reports about women - always women - who had been videoed in Marlborough and Hamilton and Auckland.

Secret filming at the Medway Secure Training Centre in Rochester, Kent, appeared to show teenagers being assaulted and staff boasting about what they had done.