Extremely low levels of radioactive iodine from the tsunami-hit Japanese nuclear plant have been detected in parts of the UK, the Health Protection Agency said today.
A statement from the HPA said the "minutest traces of iodine" were being seen in the UK, with low levels detected at monitoring stations in Oxfordshire and Glasgow.
The agency said there was no public health risk posed by the iodine, as the radiation dose received from inhaling air with the levels recorded in the past few days would be minuscule and much less than the annual background dose.
And while levels may rise in the coming days and weeks, they will be "significantly below any level which could cause harm to public health", the HPA said.
The statement comes after the Scottish Environment Protection Agency (Sepa) said an air sampler in Glasgow had picked up iodine particles which they believe could be from the Fukushima nuclear plant in Japan.
The HPA said that trace levels of the radioactive chemical iodine-131 had been detected by measurements taken at a monitoring station in Oxfordshire yesterday.
The measurements followed reports of iodine at monitoring stations in Glasgow and Oxfordshire.
Dr James Gemmill, Sepa's radioactive substances manager, said: "The concentration of iodine detected is extremely low and is not of concern for the public or the environment.
"The fact that such a low concentration of this radionuclide was detected demonstrates how effective the surveillance programme for radioactive substances is in the UK.
"Sepa has an ongoing comprehensive monitoring programme for radioactivity in Scotland and has increased the level of scrutiny to provide ongoing public assurance during this period."
Engineers have been struggling to bring the Fukushima plant under control since it was hit by the earthquake and tsunami which devastated north east Japan more than two weeks ago.
In the latest problems to hit the plant, which has suffered explosions, fires, radiation leaks and fears of a partial meltdown, radioactive water was found to be leaking from the site, while plutonium has been found in the soil.
Environment charity WWF Scotland's Dr Richard Dixon said: "The detection of small amounts of radioactivity which may have come from a damaged reactor on the other side of the planet should act as a reminder to all of the folly of nuclear power.
"We know that the majority of the public in Scotland support clean, safe renewable energy over polluting nuclear power.
"Political parties seeking votes this May should now spell out if they would oppose the building of new nuclear power stations in Scotland."
Prof Neil Hyatt, professor of nuclear materials chemistry at the University of Sheffield, said the iodine was a volatile element that only lasted for a short amount of time, so it was certain to have been produced at Fukushima and transported through the atmosphere to the UK.
"Iodine-131 has also been detected in China, Canada and elsewhere," he said.
"The Health Protection Agency equipment is extremely sensitive, so they are able to detect very small quantities of radioactivity in very large volumes of air.
"At the level detected, this quantity of iodine does not present any hazard to human health."
The chief inspector of nuclear installations Mike Weightman, who has been asked by Energy Secretary Chris Huhne to report on the implications of the Fukushima crisis for the UK nuclear industry, today set out what his inquiry will look at.
He said he would examine what had happened in Japan, looking at the power station at Fukushima and its design provisions for resilience to natural hazards, the events that occurred after the earthquake and tsunami and the actions that were taken by the operators and emergency response provisions.
He will compare UK nuclear power station designs with those at Fukushima, examine the potential threats, including natural disasters, to facilities here and any lessons that can be learnt, making any recommendations on the implications for UK nuclear power of the disaster in Japan.
But he said neither the interim or the final report will address nuclear or energy policy issues, as these are outside the role of the nuclear regulator.
The events in Japan have prompted questions over the future of new nuclear build in the UK, which ministers have said is necessary as part of efforts to ensure secure energy supplies and cut carbon emissions to tackle climate change.