Jay Morais, from Bristol, spent a year fighting Vladimir Putin’s forces on the frontline.
The 52-year-old took part in some of the bloodiest battles in the east of the war-torn country, including fighting in Donbas and the besieged city of Bakhmut.
But Mr Morais is understood to have died in hospital in Kharkiv in February, reports The Telegraph.
His Ukrainian fiance told the outlet: “I still can’t really believe he is dead.”
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