Despite being protected on paper, many of the world's and the UK's rare plants and flowers are being targeted by thieves and smugglers. From the moment a new species is discovered it can have a high price on its head, with collectors going to the ends of the earth to source a prized specimen. Tom Heap discovers how easy it is to find rare plants for sale on the net and how such trade not only threatens those plant species with extinction but could destroy the elements within them that could help in medicine.

There are five times as many plants as animals protected by CITES (Convention on International Trade of Endangered Species) meaning they can only be sold if a permit is granted but arguably there is less public concern about flora than fauna. Many orchids, cacti, cycads and various timbers are among them which the Border Force and Kew Botanic Gardens try to help monitor and police.

But not all thieves are on expeditions to remote mountains. Tom hears how many of the UK's botanic gardens have been targeted. In some cases it may be an opportunist gardener but in other cases it involves organised crime. Some gardens are using new techniques to protect specimens or simply having to keep them locked away, out of sight.

Some thefts which aren't in monitored collections may not even be discovered for months, if at all. Calls are being made for us to monitor pathways, hills and towpaths and report when plants disappear. But Tom also learns about clever new devices and scientific methods to help raise the alarm, detect illegal sales and prove guilt in the absence of a smoking trowel.

Presented by Tom Heap. Produced by Anne-Marie Bullock.