Prince William has taken a conciliatory step in his feud with Prince Harry by publicly naming him for what is believed to be the first time in six years.

Speaking in a new documentary, William recounts how Princess Diana took the brothers to a homeless shelter in London as children to show the realities of life outside the palace.

The film, titled 'Prince William: We Can End Homelessness', includes poignant unseen photos of William and Diana at the Passage in Westminster.

In one, taken when Princess Diana visited with William on 14 June 1993 just days before his eleventh birthday, the young Prince is seen studiously playing chess with a homeless man at the shelter.

Another, taken in December that year, shows a suited-and-booted young William standing alongside his mother at the shelter, his arms stuffed with presents to give.

'My mother took me to the Passage, she took Harry and I both there... I'd never been to anything like that before and I was a bit anxious as to what to expect,' explains William.

'My mother went about her usual part of making everyone feel relaxed and having a joke with everyone...I remember having some good conversation, playing chess and chatting.

'You meet people, like I did then, who put a different perspective in your head.'

The emotive opening highlights how the Prince's passion to end homelessness is driven by memories of his mother.

The film emphasises how trauma and family breakdown are common causes of homelessness, the former being sadly familiar to the Prince of Wales.

Alongside the death of his mother, William continues to be estranged from his younger brother.

Until this film, it is understood William has not uttered his brother's name in a public speech or interview since 2018 when the two princes, alongside the Princess of Wales and Meghan Markle, were interviewed at the Royal Foundation Forum.

The documentary also reunites the brothers on screen, if only via an old photo of both boys visiting the shelter in 1993.

Filming also coincided with another personal trauma: the cancer diagnosis of his wife, the Princess of Wales.

Insiders acknowledge that filming took a little longer because of everything the Prince was 'dealing with', but added he was 'very accommodating' despite the challenges.

Cameras started rolling in June last year when the Prince launched his project Homewards, which focuses on ending homelessness in six UK areas: Aberdeen; Bournemouth, Christchurch & Poole; Lambeth; Newport; Northern Ireland and Sheffield.

We see the Prince on public engagements and in interviews with the director, Leo Burley, but the palace are tight-lipped on precisely when the Prince sat down to talk.

What emerges is a Prince serious about making his mark.

'I feel with my position and my platform, I should be delivering change,' he says.

'I feel compelled to act because I don't want to just talk about it. I don't want to just listen. I actually want to see someone smile because their life has been made better. So therefore building a project is the only way I can see at the moment to try and alleviate and help people who are in a much less fortunate or a very difficult situation.'

Such a statement could be interpreted as rhetoric against traditional royal ribbon-cutting and an indication he could become a rather radical King.

William is a modern man who prefers to watch box sets rather than reading, and it's already been suggested he could be the first British monarch to break ties with the Church of England.

Others close to the current King point out that Charles was also a pioneering Prince with projects like the traditionalist Dorset village of Poundbury.

At other points in the film we catch glimpses of the person behind the prince. When meeting 21-year-old Lainey, a young girl experiencing homelessness who is training to work at Pret, he jokes: 'Listen, if anyone can figure out how to work a cappuccino machine they're amazing. Well done, honestly. Those machines, I look at them and I'm like: 'you need a degree to work this. They're crazy.'

After meeting William, she reflects: 'Even though he's like rich and people see him as some poshy...he didn't judge...I just felt like he was one of my mates'.

Other stars of the show include the Sheffield-based community activist Safiya Saeed and advocate Sabrina Cohen-Hatton, who was formerly homeless.

Homewards aims to find successful charity models, zoning in on the Salvation Army in Cardiff who brought former rough sleeper Wayne into his own home.

In a powerful scene, Wayne is brought to Windsor Castle to meet with Prince William.

Wayne's experiences are deeply moving, as is the knowledge that the meeting was filmed in the same location where the Princess of Wales filmed her cancer announcement in March.

The filmmakers also confront William about the criticism that his wealth and (numerous) homes make him an ill-suited poster boy for a homelessness project.

'I think if I answered every critic I'd be here all day,' he responds.

'Criticism drives you forward. I think it's right to question, but at the end of the day we are pushing forward to deliver change and hope and optimism into a place that frankly has had very little of it for a long time. I hope I can bring something that's not been done before.'

It's a response that might not satisfy his detractors, but it is clear that William cares deeply about the issue not in spite of his life and experiences, but because of them.

'Many people can relate to trauma. Many people can relate to family breakup and loss,' says Homewards advocate Ms Cohen-Hatton.

'I think the prince's ability to relate to people on that human level is because of some of the experiences that he's had himself.'

The two-part documentary will air on Wednesday 30 and Thursday 31 October at 9pm on ITV1 and ITVX.