With his one good hand, Brian Meagher struggled to hold his phone.

He is otherwise immobile – his other hand has been badly damaged by a bullet. Shrapnel has been lodged in his heart, spine and legs.

The three other soldiers in his hospital ward can't help either, he told Prime Time.

They’ve all had their legs amputated, a grim reminder of the human cost of the victorious offensive by the Ukrainian army in their rout of the Russians last week.

But the shaky footage that Brian recorded is still compelling. He is the odd man out in the room – the Irishman who will walk again.

He told Prime Time about his extraordinary journey from his safe job in the prison service in Dublin to fighting on the frontline in Kharkiv.

Speaking during the course of several phone calls from his hospital bed in southern Ukraine, Brian remained undeterred.

"I'd like to come back here," he said, in between a cough that clearly aggravated his lung, "because the fighters at the front need so much stuff."

Shrapnel has been lodged in Brian's heart, spine and legs

"I would maybe like to come back in the future because I know a lot of people are very afraid to go to the front. I know where stuff is needed," he said.

He was told by his doctors that he was lucky to survive.

"I still have two pieces of shrapnel in my heart. They’re still there. I have two pieces in my spine, but it went into my bone bit so I was lucky," he said.

"And, all down my leg, there is shrapnel and then there is the gunshot that hit my forearm. I’ll probably lose two fingers."

Brian fought with the foreign legion supporting the breakthrough offensive against the Russians last week – on the first day of the push through the eastern front.

"So we were deployed 10 days before the actual offensive started," he said, noting that their job was to scope out routes to some of the villages.

"We weren't going in as part of the first wave. That was going to be mechanised infantry. Their job was to smash through the Russian lines and just keep driving. And our job was to kind of mop up and to protect the 1.5mm self-propelled artillery guns."

But the unit made more progress than expected, he said.

"We ended up in enemy territory on day one – we shouldn't have been there."

Most of the Russian forces had fled, but one unit remained and it ambushed a unit from the foreign legion, including Brian's.

"I'm standing in an open-back truck, and, as this tank turned around, there was just explosions," he said.

After realising he had been hit, Brian resigned himself to the worst

"As soon as it happened, I hit the ground and I jumped up because I thought I was fine. My mind didn’t register with my body. So I started to run as I could see smoke coming from the explosion."

But, as he stated to run, he looked at his gloves and started to feel warm.

For a split second, he said, he thought he had not been hurt.

And then he took a few more steps and realised that he had been injured.

"I later found out then that I was hit twice in the heart [with shrapnel] and I got one into my spine. And I had gotten one somewhere over in my lung area," he said.

"Fluid was filling up my lungs, because I was struggling to breathe. It was like I was slowly drowning. And I hadn't realised I had been shot at that time."

Brian had resigned himself to the worst, and pulled his protective clothing off.

"It just got so bad that I said 'right, if I'm going to die, I'm going to die comfortably.

The ambush team were forced to flee the town. They left around 10 casualties behind him, including a man who was an American Green Beret for 20 years.

"He's missing. So they are combing the morgues looking for him," he said.

So how did this 35-year-old father of two from Ratoath in Co Meath end up fighting on the front line last week?

Brian was a member of the Irish defence forces for 15 years

"I spent 15 years in the Irish army. I joined when I was 17 and I left the army around 2018. This is where the roles have led me."

He told Prime Time that he was watching the news, and because of his background, he felt compelled to fight.

The deaths of civilians in the town of Bucha also had an impact.

"They needed soldiers. So I just decided to go. I knew no one here. I just bought all the equipment, and I came over."

So how does his wife and his two children feel about all of this?

"I told them I was going to train people, which I ended up doing. But I never said fighting."

Doctors say he was lucky to survive and that his recovery will be slow.

But his only regret is that he wishes he could have done more.

"I regret that I got hit so quickly in the offensive. I just wanted to do more. I couldn't, so that's probably my only regret," he said.

"I'm very glad I came here. I know if Ireland was invaded, I would want Europeans and foreign men to come and help us fight. So that's all, that's all I did."