Jordan Gatley was shot dead in the city of Severodonetsk in eastern Ukraine.
He left the British Army in March and travelled to Ukraine to help forces there “after careful consideration”, his father said.
It takes a lot of courage to leave home and go thousand miles to defend what you believe in. Just because the heart says so. Because you can't stand the evil. Jordan Gatley was a true hero. We will always remember his contribution to the protection of Ukraine and the free world. https://t.co/VZkRGnya1G pic.twitter.com/CWQHZ2wEJi
— Михайло Подоляк (@Podolyak_M) June 12, 2022
Dean Gatley, who said his family was informed on Friday of his son’s death, told of his pride in his actions, adding that he will “forever be in our hearts”.
Mr Gatley, who it is understood had served as a rifleman with the Edinburgh-based third battalion of The Rifles, was also praised by Mykhailo Podolyak, an adviser to Ukrainian president Volodymyr Zelensky.
Mr Podolyak said the Briton will always be remembered for his contribution.
Alongside a picture of Mr Gatley standing in uniform with his father, Mr Podolyak wrote: “It takes a lot of courage to leave home and go thousand miles to defend what you believe in. Just because the heart says so. Because you can’t stand the evil.
“Jordan Gatley was a true hero. We will always remember his contribution to the protection of Ukraine and the free world.”
He loved his job and we are so proud of him. He truly was a hero and will forever be in our hearts
Mr Gatley said his son had been helping to train Ukrainian forces and had told him the missions they were going on were “dangerous, but necessary”.
In a Facebook post, his father wrote: “We have had several messages from his team out there telling us of his wealth of knowledge, his skills as a soldier and his love of his job.
“His team say they all loved him, as did we, and he made a massive difference to many people’s lives, not only soldiering, but also by training the Ukrainian forces.
“Jordan and his team were so proud of the work they were doing and he often told me that the missions they were going on were dangerous, but necessary.
“He loved his job and we are so proud of him. He truly was a hero and will forever be in our hearts.”
A spokesman for the Foreign Office said: “We are supporting the family of a British man who has died in Ukraine.”
In April, tributes were paid to Scott Sibley, a British military veteran reportedly killed in Ukraine while fighting against Russian forces.
At that time the Foreign Office confirmed a British national had died in Ukraine.
A small number of serving British personnel are believed to have gone absent without leave to join the resistance against the Russian invasion, while veterans and Britons without combat experience are thought to have also travelled to Ukraine.
There was initially confusion on the Government’s position after Foreign Secretary Liz Truss, in comments during an interview to the BBC on February 26, said she would “absolutely” support UK nationals who chose to fight for Ukraine.
However, she later rowed back on those comments, insisting she had been “expressing support for the Ukrainian cause” in her remarks, and that there are “better ways” to contribute to the country’s defence.
Veterans minister Leo Docherty has previously written to armed forces charities to encourage those tempted to travel to the war zone to turn their efforts to helping the Ukrainian people from the UK.