17 January 2015
Last updated at 09:39
The number of drug seizures in prisons in England and Wales has significantly increased, figures from the Ministry of Justice show.
In the year to the end of March 2011, there were 3,700 drug seizures and in 2013-14 that number had increased to nearly 4,500.
Three privately run jails recorded the most drug finds.
Ministers said the figures showed security measures, including sniffer dogs, were working.
Security procedures in prisons also include intelligence-led searches.
Last year there were 1,300 seizures of cannabis and cannabis plants, up slightly on the figure four years ago.
The biggest rise was in the category including legal highs, such as Spice, which is believed to be a factor in prison violence, drug debts and bullying.
BBC home affairs correspondent Danny Shaw said drugs were entering prisons by being smuggled in or thrown over perimeter walls.
He said the drug Spice, which is also known as Black Mamba and is a synthetic form of cannabis that is cheaper than the real thing, was very difficult to detect on prisoners using conventional drug testing equipment.
“This is a real challenge for the authorities, they are training drug dogs to sniff [Spice] out, and they are trying frantically to get some sort of drug testing that does work,” he added.
The three jails recording the most drug finds according to the figures were Doncaster, Forest Bank in Greater Manchester and Altcourse in Liverpool, all operated by private companies.
A Ministry of Justice (MoJ) spokesperson said: “It is simply illogical to say that our drugs strategy is failing because of the number of seizures. What this in fact shows is that our robust security measures, which include the use of intelligence-led searches and specially trained drugs dogs, are working.”
The spokesman added that the numbers of prisoners testing positive for drugs had fallen over the past 15 years.