[3] It is partnered with 1 Military Intelligence Battalion, a Regular Army unit based in Catterick Garrison, North Yorkshire.

The Cold War TA PI specialism was initially provided by the Intelligence Corps TA in the Army Photographic Interpretation Unit (APIU)[12] in Borers Wood, London, the Army Photographic Interpretation Centre (APIC) at RAF Wilton[13] and latterly with the Joint Air Reconnaissance Intelligence Centre (JARIC) at RAF Brampton.

The initial establishment included a national unit, 20 Security Company (V), which used Intelligence Corps TA drill halls in the UK.

On 1 April 1999, the TA Intelligence & Security Group (V) was renamed 3 MI Bn (V), with its headquarters in Worship Street, London.

It maintained sub-units in Worship Street, Hampstead, Birmingham, Edinburgh, Bristol, and York with detachments in Exeter, Cardiff, Gateshead, Belfast and Chorley.

After the 11 September attacks on the World Trade Centre in 2001, 53 volunteers from 3 MI Bn (V) were mobilised in support of the War On Terror (Op VERITAS).

They were employed in a variety of strategic and operational locations, with a large contingent serving in Defence Intelligence in Whitehall, London.