By Angus Crawford
The government has organised the disposal of 9,000 radioactive items to stop them falling into the hands of terrorists, the BBC has learned.
There are thought to be 11,000 radioactive items in the UK
The items come from hospitals, schools and private firms. The Environment Agency's programme of disposal has been running since 2005.
The effort is also designed to prevent the materials going missing and becoming a hazard to the public.
The final cost of getting rid of these "surplus sources" is likely to be £7m.
There are thought to be 11,000 radioactive items in the UK, owned by universities, schools, hospitals and private firms, which are no longer used.
In hospitals, they might be highly active sources as large as a desk which were used in radiography machines.
Private companies often use radioactive elements in measuring devices and military museums have the dials of World War II aircraft which are covered in radioactive paint.
Clive Williams, from the Environment Agency, said a sample could be "the size of a finger tip" or much larger.
"Eventually it will come to end the end of its useful working life and when it reaches that point it needs to be properly and safely managed and disposed of," Mr Williams said.
The enormous cost of disposal in the 1990s meant that many organisations simply stockpiled their surplus sources.
Mr Williams said this now presented "a security threat".
The risk is that terrorists could get hold of the material and use it to make a so-called dirty bomb, designed not to kill but to spread low-level contamination.
"I wouldn't say these are weapons of destruction, so much as disruption," Mr Williams said.
So, working closely with the police and MI5, the Environment Agency began the Surplus Sources Disposal Programme (SSDP) and so far its tally of items has reached 9,000.
The programme is due to finish next year.
Mr Williams said: "We are very keen to ensure those security issues are dealt with and that the proper protections are provided.
"People in the UK should sleep easier, just that bit easier, knowing that there aren't these sources out there."
Ian Day, who trains companies and individuals in radiological awareness, said: "This is excellent news.
"If you look at November alone, around the world people have dumped radiation material to get rid of it. People have been paid to dump radiation material.
"This programme is a way of preventing dumping in this country."
News of the SSDP programme was also welcomed by Shaun Burnie, an independent nuclear advisor, who used to run Greenpeace's nuclear campaigns.
But he said many of the sources were being taken for storage at nuclear plants such as Sellafield or Drigg, a practice he said was not sustainable.
"As the government well knows, they have no long-term safe option on the table for the disposal of nuclear waste," Mr Burnie said.
"To pretend otherwise is dangerously misleading."