That VC10 site that ricardian references is fascinating.
The VC10 Sniffer Role
Around the time of the UK's first nuclear bomb tests, Operation Grapple in March 1957, Canberras had been modified to act as sniffers, so that they could take samples of the bomb's mushroom cloud. The evolution of the Cold War meant that a capability to collect high altitude air samples for detection of nuclear material continued to be useful. The Vulcan B.2MRR version as operated by no.27 squadron, originally modified for Maritime Reconnaisance, was the next type to be tasked with this and could carry two sampling pods below its delta wing. Between 1973 and 1982 these Vulcans, re-designated as SR2s, carried out the sampling task.
After no.27 squadron stood down, the next type to be sent out to collect air samples was the VC10. At least two of the K3s were modified so that they could be sent out on this air monitoring role. Officially the role is called Meteorological and Atmospheric Research but the main job is collecting dust samples and monitoring and recording of airborne radiation. When needed, the K3 tanker is modified so that it carries two sampling pods on its wing stations instead of the refuelling pods, and a smaller instrument underneath the nose of the aircraft. Inside, an operator's station is provided on the left side of the cabin, on the rear face of the toilet cubicle.
From information released to the press we know that ZA150 was sent to Kadena Air Base, Japan, in October 2006. In May 2009 a K3 was again sent to Japan to collect information on North Korea's next nuclear test. The purpose of these flights is to gain information on the composition and yield of the weapon used, but information about the distribution of any fallout is also useful and this ties in to the meteorological aspect of the role.
As recently as 2006! I wonder what aircraft is used for this kind of task today?
<<Edited to say>>
The VC10 and Lockheed TriStar tanker/transports were replaced in RAF service by the Airbus A330 MRTT Voyager under the Future Strategic Tanker Aircraft Project. The type's final flights in RAF service took place on 20 September 2013, the final refuelling sortie was followed by a tour of the UK. On 24 September, ZA150 made its last flight to Dunsfold Aerodrome for preservation at the Brooklands Museum, while ZA147 arrived at Bruntingthorpe on 25 September.>> From Wikipedia
