Senior commanders say foreign agents are behind some 18 drone sightings above UK military hubs and power stations during a two-year period.
Among the areas believed to have been targeted is the Royal Navy’s nuclear submarine base in Faslane, Scotland.
The site is home to the Trident submarines and nuclear weapons, which are stored at the Royal Naval Armament depot at the site.
The disclosure follows warnings by intelligence chiefs that China is intent on stealing our most sensitive secrets.
The details of the drone activity were uncovered under freedom of information laws, reported by Scottish paper, The Daily Record.
Lieutenant Colonel Philip Ingram, a former intelligence officer, said: ‘The Chinese have a very mature and sophisticated espionage programme running throughout the UK.
‘Business, academic research, manufacturers, supply chains, politicians, police, the military and civil servants and more are targets.
‘Many will have been compromised, often without realising what has happened.’
It is not known whether any military bases in the Portsmouth area have been targeted.
The city is home to the Royal Navy’s HQ, as well as naval training facilities HMS Sultan, in Gosport, and HMS Collingwood, in Fareham.
Also based in the area are key munitions plants and research facilities, at Broad Oak, in Hilsea, and at the Portsdown Hill Technology Park.
The Atomic Weapons Establishment in Aldermaston, Berkshire, where nuclear warheads are designed and made, is also said to have been targeted.
The sightings happened between 2019 and 2021 but details of the military bases were withheld for defence and national security reasons.