Breaches of no-fly zones around British nuclear plants are raising fears of a terror attack, an allegedly leaked parliamentary report says.
Many could be killed in a worst-case scenario
More than 100 reports of breaches have been filed by 19 nuclear sites over the past five years, New Scientist said.
The incidents raise the prospect of terrorists flying a hijacked plane into a reactor, possibly killing millions in a worst-case scenario.
But the British Nuclear group said such a scenario was implausible.
New Scientist said it has seen a copy of a report by the Parliamentary Office of Science and Technology, which looked at risks of a terror attack on a nuclear facility.
Since the 2001 attacks in New York and Washington DC, the no-fly zone around nuclear sites in the UK has been doubled.
Aircraft are now banned from flying within a two-nautical-mile (3.7 kilometre) radius of a nuclear facility, and must also stay above a certain height which varies according to the location.
But these restrictions have been flouted on numerous occasions, the scientific journal reports.
Declassified reports from the Ministry of Defence (MoD) revealed 56 breaches by military aircraft between 2000 and 2003.
Four complaints came from the MoD's own nuclear weapons sites at Aldermaston and Burghfield in Berkshire, and Faslane near Glasgow.
On one occasion in April 2002, a plane flew so close to the
Torness reactors in East Lothian, Scotland, that three intruder alarms were triggered.
And last year, three military planes were spotted practising for a flypast for
the Queen's birthday near the Sizewell site in Suffolk.
In all there were 71 complaints of civilian aircraft straying into no-fly zones since the beginning of 1999, said the magazine.
The Civil Aviation Authority (CAA) had sufficient evidence to launch formal investigations in 12 cases, including two at the Sellafield plant.
In March the operators of Sellafield denied claims that an RAF jet came within a second of crashing into it. New safety structures are due to be erected at the plant.