Line of Duty’s Vicky McClure reenacts the D-Day heroics of her veteran grandfather Ralph

Her gun-toting, hardened cop character Kate Fleming is about as tough as they come.

But Line of Duty’s Vicky McClure seemed out of her depth as she waded in and out of the sea in full battle dress as she attempted to experience what it was like for troops during the Normandy landings.

In a thick woollen Second World War uniform and helmet, holding a backpack and a rifle, the actress was trying to better understand what her D-Day veteran grandfather Ralph, 98, went through on June 6 1944, when he was among more than 150,000 soldiers and sailors sent ashore under murderous shelling and gunfire.

In a clip from the forthcoming ITV documentary My Grandad’s War, Ms McClure, 40, walks as far as she can out to sea before turning and trying to wade back to the beach.

Historian Stephen Fisher said many landing crafts could not get close to the beach so soldiers were forced to wade through cold water, with many not making it to shore.

In a thick woollen Second World War uniform and helmet, holding a backpack and a rifle, the actress was trying to better understand what her D-Day veteran grandfather Ralph (pictured left with Vicky McClure, right), 98, went through on June 6 1944, when he was among more than 150,000 soldiers and sailors sent ashore under murderous shelling and gunfire

Ralph left school at 14 and became a butcher. Two years later he joined the Navy and became a signalman, despite never having been to sea. While visiting the British Normandy Memorial, which readers of the Daily Mail donated more than £1million to help build, Ms McClure fought back tears

‘For the average infantryman landing on D-Day, as well as that battle dress, which would absorb a lot of water, they’re carrying very heavy webbing equipment loaded with ammunition and their small pack on their back with 48 hours-worth of supplies,’ he said. 

‘And of course, their boots virtually filled with water as soon as they stepped into the sea.’

Nottingham-born Ms McClure struggled to get to shore, saying: ‘My God, this is the heaviest feeling. Ahh, it weighs more than me. How did they do it? I tried to run as fast as I could, but the weight of all this…

‘It’s not that choppy out there. It’s shallow. It’s flat. It’s sunny. It wasn’t that cold. But trying to run back, you know, I’d have died for sure.’

Ralph left school at 14 and became a butcher. Two years later he joined the Navy and became a signalman, despite never having been to sea. 

While visiting the British Normandy Memorial, which readers of the Daily Mail donated more than £1million to help build, Ms McClure fought back tears.

She told Radio Times: ‘When you feel so connected to someone who went through what he went through in the war, you are going to feel emotionally charged all the time. The trip was a joy, but I did struggle to hold it together.’

‘There were people who’d travelled a very long way, some of whom had connections to the war, who were honoured to be in Grandad’s presence,’ she said. ‘There are only so many people left from that day and my Grandad is one of them.

‘I was like, ‘Grandad is the big deal. Nobody wants a selfie with me anymore!’ I hope young people will engage with the documentary and learn things, too – there is a war happening now and thousands of people have offered to fight, whether they are from Ukraine or not.

‘There is still a desire to protect humanity. Maybe My Grandad’s War will give people a chance to reflect on where we’d be if the Allies hadn’t won.’