Colonel Andrew Ryan studied Architecture at the University of Bath and was commissioned into Bristol UOTC, serving as a member of the Royal Engineers Troop. 

Moving to the University of Portsmouth in 1990, he joined 2nd Battalion the Wessex Regiment as a Platoon Commander.  After 7 years in the Infantry, he transferred back to the Royal Engineers and became a Troop Commander at 227 (Amphibious) Engineer Squadron, part of the newly formed 78 Engineer Regiment. He commanded a hybrid Regular / Reserve Troop. 

Posted to London UOTC as 2IC of C Company, he promoted to Major and took up command of Athlone Company, the infantry training company, as the first non-infantryman to do so.  Service at HQ London District at staff followed, in the role of Senior Watchkeeper, G3 UKOPS.  He was then selected to become 2IC of Oxford UOTC in 2009. 

In 2011 he promoted as SO1 Infrastructure, 64 Works Group RE.  Deploying with the unit on Op HERRICK 20, he acted as Joint Force Engineer in theatre.  On return he served as Deputy President, Army Officer Selection Board at Westbury.  He attended both TACSC and ACSC(R) and returned as Directing Staff on ACSC(R) in 2013. 

He assumed command of 65 Works Group RE in September 2016, commanding these specialist Infrastructure Engineers. Highlights included designing a new port for the Latvians. Selected for promotion post command, he became Corps Colonel Reserves Royal Engineers in November 2019. He is now the first incumbent of the newly formed post of Deputy Commander Multi National Military Engineer Brigade (MNMEB) at HQ Allied Rapid Reaction Corps. He undertakes this role alongside holding the post of ACOS Engineers in the Engineer Branch.