The average unit tour intervals for the Infantry and those units of the Royal Regiment of Artillery, the Royal Armoured Corps and the Army Medical Services which deploy as fully formed units, are 23.5, 20.8, 23.1 and 24.5 months respectively. This is calculated on the basis of the mean time between the start of the most recent deployment and the end of the previous deployment.
The Household Cavalry has only deployed as a unit twice since January 2003: Iraq (April 2004-October 2004) and Afghanistan (October 2007-April 2008). As such, its average unit tour interval and actual unit tour interval is 35 months.
The unit tour interval is a less relevant measure when applied to the Corps of Royal Engineers, Royal Corps of Signals and the Royal Electrical and Mechanical Engineers. This is due to the frequency with which personnel move between formed units within these Corps (the personnel deployed with a unit will be substantially different from the personnel deployed with the same unit on a previous occasion). Consequently, unit tour interval data for these Corps are not routinely collated.