Ritchie was
commissioned into the
Royal Artillery on 10 March 1973 as a
second lieutenant. He was promoted to
lieutenant on 10 March 1975, and to
captain on 10 September 1979. He saw service in
Belize,
Rhodesia,
Northern Ireland and
West Germany from 1974 to 1984. Having attended the
Staff College, Camberley, he was promoted to
major on 30 September 1985. He then was posted to the
Ministry of Defence in 1986–1987 before joining the
3rd Regiment Royal Horse Artillery, with which he served in Germany,
Cyprus, and the United Kingdom from 1988 to 1990. He was Director of Army Plans from 1990 to 1992, then commanded the
1st Regiment Royal Horse Artillery from 1992 to 1995. He was promoted to
colonel on 30 June 1995. He saw service in
Bosnia from 1995 to 1996. He was promoted to
brigadier on 31 December 1996 with seniority from 30 June 1996, before taking the
Higher Command and Staff Course in 1997. He was Director of Personal Services (Army) from 1998 to 2000 and was at the
Royal College of Defence Studies in 2001, then was Director of Corporate Communications (Army) in 2001–2002. He served as
Commandant of the Royal Military Academy Sandhurst from 5 January 2003 to 2006.
Commandant of Sandhurst Ritchie's tenure as Commandant of Sandhurst coincided with the attendance of
Princes William and
Harry at the academy, but was marred by a series of high-profile security breaches by journalists. In June 2005, a tabloid reporter successfully smuggled a fake bomb into the academy, and also claimed to have filmed Prince Harry in the supposedly secure military compound. The incident prompted a full security review by
Defence Secretary John Reid. In August 2005, a journalist for another tabloid was successfully offered a job at Sandhurst despite using obviously fake credentials. Ritchie resigned as Commandant of Sandhurst in April 2006, resigning from the army shortly thereafter. After leaving Sandhurst, Ritchie instructed media law firm
Harbottle & Lewis, who successfully sued the
Daily Mirror on his behalf over a front-page story (subsequently repeated in the
Daily Express and
The Times) headlined, "Harry's Army Chief quits 'over stress'", and "Fall Out! Exclusive: Sandhurst chief quits job after stress of looking after Princes".
The Mirror offered a full retraction, paid an undisclosed sum in damages (Ritchie's writ had been for £100,000 in damages), plus legal costs, and accepted that as an army officer, Ritchie, "has been trained to deal with stress." In an interview with Ritchie after his retirement,
The Daily Telegraph noted, "There were conflicting reports that 52-year-old Gen Ritchie had either been forced out, or so stressed by the security scare that he opted for early retirement", which Ritchie dismissed as "complete rubbish". ==Later life==