Which organization is linked to Gareth Keenan's claimed lieutenant status?

Gareth Keenan's claimed lieutenant status is linked to the Territorial Army. In The Office, Gareth proudly presents himself as a military man and uses his alleged rank to give himself extra authority at Wernham Hogg.

The Territorial Army was the former name of Britain's part-time volunteer military reserve, now known as the Army Reserve. Gareth's military experience becomes a recurring source of both comedy and office intimidation, as he boasts about combat skills, discipline and army procedures.

The key word is “claimed”: the series treats Gareth's lieutenant status with comic scepticism rather than presenting him as a genuinely formidable officer. Tim and Dawn frequently exploit his pride in military service by asking suggestive questions about army life that Gareth fails to understand.

This is sometimes confused with the Royal Army, Royal Air Force or Royal Navy. However, Gareth's specific affiliation is the Territorial Army, and his rank is presented as part of his exaggerated self-image.