A BELGIAN plane used by Nato for international surveillance of air space was spotted circling over the area on Monday.
The Ministry of Defence said the plane was a Nato Boeing E-3 Sentry, which is an Airborne Warning And Control System used primarily to detect other planes.
It travelled from Belgium and flew in large circles at 33,000 feet but didn’t land in the United Kingdom.
It was spotted for miles around as the sunny conditions meant visibility was perfect from the ground and the Mercury received calls from people in Stamford and Ketton who spotted the aircraft.
A spokesman for the Ministry of Defence said: “We have known about this training exercise for a long time.
“They were lucky because it was a perfect day for it with clear skies, which meant the plane was also clearly visible from the ground.
“We did get some phone calls and we can confirm it was a Nato aircraft.
“The exercise was planned and everybody knew about it.”
The spokesman also confirmed the plane had come over from Belgium on the day but did not land in the United Kingdom.
The plane was flying at about 33,000 feet and, although it can stay in the air for up to 10 hours, was over the area from about 7.30am until 11.35am.