The Motor Machine Gun Brigades were formed in May and June 1940. They were formed to provide a rapid reaction force to the potential invasion threat.
| Date formed: | 23 June 1940 |
| Date disbanded: | 01 December 1940 – Reorganised and redesignated as 28th Armoured Brigade. |
| Commander: | Brigadier H. Lumsden |
| Units | |
| 5th Dragoon Guards | 23 June 1940 to 30 November 1940 |
| 15th/19th Hussars | 23 June 1940 to 30 November 1940 |
| 1st Fife and Forfar Yeomanry | 23 June 1940 to 30 November 1940 |
| Higher formations served under: | |
| Western Command (UK) | 23 June 1940 to 18 November 1940 |
| 4 Corps (UK) | 19 November 1940 to 30 November 1940 |
