A dog at Norwich prison has become the first in the world to be trained at sniffing out inmates' mobile phones.
The success of spaniel Murphy has led to other prisons recruiting dogs, which can be trained in a matter of weeks.
"Everything has its own unique scent - once you find that scent you can then get the dog to look for it," said Murphy's dog handler Kevin Spencer.
The smuggling of mobile phones into prisons in England and Wales has more than doubled since 2007.
In 2010 more than 10,000 mobile phones and Sim cards were confiscated.
Inside prisons basic models can be exchanged for hundreds of pounds, with camera phones fetching around £900.
The video appeared as part of
BBC Inside Out East
broadcast on 7 February 2011.