Horton, who captained the Hatters to promotion into the top-flight in the 1981-82 season, took part in an annual health check-up in early April as part of his long-term affiliation with the LMA – and the results flagged up the disease a month later.

The 74-year-old is now encouraging more men to know their risk of prostate cancer, the most common cancer in men, by taking Prostate Cancer UK’s 30 second risk checker.

You can check your risk in the next 30 seconds at prostatecanceruk.org/riskcheck.

The hugely respected Horton took charge of well over 1,000 matches in a distinguished managerial career and also led Hull City, Brighton & Hove Albion, Port Vale and Oxford United, as well as coaching many more clubs.

He also played for Brighton, Vale and Hull before transitioning into player-management when joining the Tigers. Horton returned to Macclesfield in 2012, but resigned after eight games.

And on the eve of the Premier League clash between two of his former clubs, Manchester City and Brighton, he decided to talk about his diagnosis, including a former England striker who convinced him to go public and the son of a Man City legend who is helping him navigate his treatment.

“Until this happened, I didn’t know anything at all about prostate cancer; I never dreamed this would happen. So I’m hugely grateful and thankful to the LMA for the work they do as they are saving lives,” said Brian, who reserved special praise for Doctor Sally Harris who oversaw the check-up and initially flagged the potential danger of prostate cancer.

“Even now I feel as fit as I anyone. I didn’t feel any different before the LMA check. I wasn’t going to the loo more or anything; there were no symptoms. Probably in our era, you think you are okay, you think you are invincible.”

Cancer has affected Brian’s family with his brother currently affected by another version of the disease.

He added: “Cancer is such a big word, isn’t it? A word that everybody dreads. The biggest thing you think about straight away is your family and telling them. But I’m also really committed to talking about this, telling my story and making men more aware of the risk of prostate cancer. That will hopefully ensure others aren’t walking around unaware.”

Among the long list of people he wanted to thank included former colleague at Hull City and current assistant manager at Wrexham, Steve Parkin, who convinced him to complete the check-up.

And those supporting him as he plans for brachytherapy - a type of radiotherapy where tiny radioactive seeds are put into your prostate - include Doctor Jon Bell, son of arguably Manchester City’s greatest ever player, Colin Bell.

Brian continued: “The first time we talked about it was during the FA Cup final between City and United at Wembley. I pulled Jon aside for a few minutes and he was so calm and talked me through things. Him, and all the doctors and nurses have been hugely supportive.”

Brian’s treatment will begin towards the end of the year, and he was persuaded to speak out by former England striker Mick Harford, while he has the support of some of his former teammates at Luton Town, the third current top-flight club he is associated with.

“I saw Mick Harford at the Brighton versus Luton game, and Mick (who has prostate cancer himself) asked me if I was going to talk publicly about it. I’d been discussing it with people, with my wife and family and it was Mick who made me realise that it was very, very important. If it helps other men at risk of prostate cancer seek advice from their GP, then I think it’s worthwhile doing it.”

The news about Brian strengthens the relationship between Prostate Cancer UK and the LMA with the two organisations closing in on a decade of lifesaving work.

LMA Chief Executive Richard Bevan said: “Our members' health is extremely important to us and remains a significant area of support that we provide to them and their families

“The LMA is proud to have built such a strong and powerful partnership with Prostate Cancer UK. Our members have engaged magnificently with the charity’s work in so many different ways for more than nine years now, and that work has proved to be life changing.”

Prostate Cancer UK Chief Executive, Laura Kerby, said: “Brian’s story is a stark reminder of the dangers of prostate cancer, the most common cancer in men. Unfortunately, early prostate cancer usually doesn’t have any symptoms, which is why men need to be aware of their risk and should take our online risk checker to find out more.

“It's encouraging to hear his treatment path is underway and we thank him for speaking out about prostate cancer in the football community. We are proud at our long-term partnership with the League Managers Association and their members and that’s been critical in delivering this important message.”

Prostate cancer is curable if caught early, but early-stage prostate cancer often has no symptoms, so it is vital that men know their risk. Men are at higher risk if they are over 50, Black or have a father or brother who has had prostate cancer.

More than 1.86m people have completed Prostate Cancer UK’s award-winning risk checker. You can check your risk in the next 30 seconds here: prostatecanceruk.org/riskcheck