The British Ministry of Defence (MOD) does not hold information on personnel who have changed their nationality from Commonwealth to British.

However, there were:

• 153 personnel who had British as their first nationality and a Commonwealth country as their second nationality (although the MOD cannot accurately tell if they joined the British armed forces directly from a Commonwealth country before changing their nationality).
• 35 personnel who had a Commonwealth country as their first nationality and British as their second nationality (although the MOD cannot tell if they had British nationality on joining the British armed forces or whether they acquired it 5 years after joining direct from a Commonwealth country).

Reference

FOI 2017/08191 dated 25 September 2017.