Dorothy Margaret Greig née Hannah was born in Gosforth in 1922 and educated at Central Newcastle High School from where she won a scholarship which enabled her to enter Newnham College, Cambridge.

A talented mathematician, she earned a first in the notoriously tough mathematical tripos examination. In 1943 she became a scientific officer at the Ministry of Aircraft Production, working in the Air Warfare Analysis Section, joining over a million other men and women who served or supported Bomber Command.

Bomber Command played the central role in the strategic bombing of Germany in WWII, carrying out vital and dangerous work, it significantly contributed to the outcome of the war. At the outbreak of war the rules of engagement agreed to by the British confined bombing to military targets and infrastructure such as ports and railways. Bomber Command first concentrated on a doctrine of precision daytime bombing, relying on sight to hit targets and avoid civilian casualties. Cloud cover and industrial haze frequently obscured targets so bomb release was made by dead reckoning — the bombers dropping their loads according to the estimated arrival time for the target. Daylight bombing resulted in heavy losses since fighter interception became easy and Command switched to night bombing. This allowed the bombers a better chance of survival, but the problems of enemy defences were then replaced with the problems of night navigation and target-finding.

Margaret Greig worked on calculations relating to the navigational accuracy of bombing, contributing to the development of pioneering new technologies that contributing to the eventual victory in Europe. The longer range, higher speed and greater bomb capacity Halifax and Lancaster aircraft came into service and the new technology meant that by the end of WWII Bomber Command was capable of putting 1,000 aircraft over a target without extraordinary effort and predictably delivering bombs within 25 yards of a target, compared with statistics that recorded that most bombs in 1941 did not fall within five miles of their target, resulting in civilian casualties.

After the war, Hannah lectured at Leeds University and worked on the theory of worsted spinning, especially the superdraft system for which she was awarded the 1959 Warner memorial award for ‘outstanding work in Textile Science and Technology’. Hannah married Alexander Greig in 1948, they had three sons and a daughter. Margaret continued to work in academia, becoming a Senior Lecturer at Constantine Technical College and then Durham University. She published several mathematical text books, successfully combining a full-time career in academia with a growing family.