Lance Corporal Isimeli Baleiwai, who is married to a British woman and has two British children, applied for British citizenship in March this year as he was leaving the Army in June.
Foreign and Commonwealth soldiers can apply for Indefinite Leave to Remain after four years service and citizenship after five years service.
But the UK Borders Agency rejected his application as the 32-year-old had faced disciplinary action for fighting with a colleague in 2010.
LCpl Baleiwai was assessed to have a criminal record as a result of the ten-minute military hearing, even though he did not ask for legal advice, did not see the evidence and was not aware that five of his colleagues were prepared to testify that he had acted in self-defence.
The former soldier has served five operational tours, including to Afghanistan and Iraq, and was able to provide a character testimony from his CO who described him as ‘a natural leader, trusted and thought very highly of’ but refusal was automatic due to his disciplinary history.
LCpl Baleiwai and his family are fighting the decision with the help of the charity Veterans Aid.