In the last five years, 23 flights carrying Defence Nuclear Materials (DNM) were undertaken. All flights were between the UK and the United States on fixed wing aircraft under the control of UK Armed Forces. No such flights passed over Scotland, or involved the use of helicopters.
I am withholding details of the physical state, mass and radiological quantity of DNM transported as disclosure would or would be likely to prejudice national security.
The transport of DNM is carried out to the highest standard in accordance with stringent safety regulations. In over 50 years of transporting DNM in the UK, there has never been an incident that has posed any radiation hazard to the public or to the environment.