Geoffrey Regan was a History Master at Charterhouse School, Godalming and Deputy Headmaster and Acting Headmaster at Halliford School.

He wrote 30 historical and educational books including, Military Blunders, More Military Blunders, Naval Blunders, Historical Blunders, Royal Blunders, Flying Blunders, Blue on Blue and Fight or Flight.

He was the Series Consultant for Channel 4's 'Great Military Blunders' series, broadcast in 2000 and Historical Consultant for ABCs 'Blue on Blue' that same year.