Against a backdrop of needing to remove five battalions from the infantry order of battle as part of the wider Army 2020 structure, a number of criteria were applied by the Army which were: maintaining a regimental system which is largely regionally aligned; demographic sustainability of regiments according to projected regional supply of recruits; proportionality of outcome, with no cap badge deletions and no regiment losing more than one battalion in a re-organisation; balancing the whole infantry structure to maintain variety of roles and parity of opportunity of experience for officers and soldiers; taking account of previous decisions on mergers and deletions; historical manning performance; and ensuring a solution that the Army would see as fair and equitable.
Based on demographic data available from the Office of National Statistics for the age cohort across the UK from which infantry recruits are drawn, and historical trends in terms of the percentage of that cohort likely to join the Army, an assessment was made of which regiments were likely to be the least sustainable in the future if they retained their current structure. This work also included a comparison of each regiment's historical outflow so the likely recruiting requirement could be determined.
The analysis showed that those regiments likely to be the least sustainable in future were the Royal Regiment of Scotland (predicted to be 1.75 battalions short), The Yorkshire Regiment (predicted to be 0.8 battalions short), The Mercian Regiment (predicted to be 0.56 battalions short) and the Royal Welsh Regiment (predicted to be 0.55 battalions short). It was therefore decided to remove one battalion from each of those regiments.
After the removal of four battalions, the method for predicting future sustainability became less statistically discerning. Therefore to determine the fifth battalion to be removed from the order of battle required the application of criteria that went wider than demographics. Historical manning performance and the need to maintain equity of opportunity meant that the Royal Regiment of Fusiliers (with average historical undermanning of 13.3% since the previous reorganisation of the infantry in 2007, and being a regiment with two battalions) was the next appropriate regiment from which to withdraw a battalion.
The analysis showed that after the withdrawal of five battalions from across the infantry, future manning should be sustainable with sufficient recruits predicted to fill the necessary posts across all battalions.