Hugh Debbieg was born in 1731. He had been a cadet gunner in the Royal Artillery and studied at Woolwich, and then a practicing engineer lieutenant in Brabant. He joined the survey in 1748 and remained for a year before being transferred to Chatham. He then had a distinguished career as an army engineer including chief engineer at Chatham, but also served with Wolfe in Canada. As a colonel in 1782, he was court martialled for disagreeing with Charles Duke of Richmond, and temporarily censured. However became lieutenant general in 1798 and full general in 1803. He was a lifelong friend to William Roy as well as a military colleague.