A phantom helicopter which was spotted hovering above Derbyshire may have been operated by IRA terrorists, newly-released information shows.
Secret Special Branch documents reveal detectives desperately tried to hunt down the daredevil pilot making night-time flights over the county.
The mystery chopper was seen above Derbyshire on numerous occasions during the winter of 1973-74 – including over Chatsworth House, Hathersage and Buxton.
By November 1973, detectives had received 12 reports of helicopters “apparently practicing landings in the vicinity of quarries and explosive stores in the Derbyshire countryside”.
Two police officers saw the chopper at close range and identified it as a two-seater Bell 206A Jet Ranger, capable of carrying five people and with a range of 250 miles.
A Special Branch memo said: “The IRA has access to and is believed to have used a helicopter for training purposes in the Derbyshire area.
“There is a strong possibility of these flights being of an illegal nature.”
Police asked Special Branch to set up a national helicopter index listing all 340 machines owned by companies and private individuals.
They also asked for discreet inquiries to be made into any former armed forces pilots who might be IRA sympathisers.
Dr David Clarke, a lecturer in journalism at Sheffield University, uncovered the information under the Freedom on Information Act.
He said: “The devil-may-care antics of the pilot smacks of a James Bond plot.
“There was even talk of using the Harrier jump jet to intercept the mystery helicopter at night over the Peak District.”
However, the mystery remains unsolved to this day.
Tabloid newspaper headlines were dominated by news of the unfolding drama at the time.