He has faced temperatures of -6C (21F), walked injured through torrential rain and battled on through storms Ciara and Dennis – all in just a pair of skimpy swimming trunks.

On Saturday Michael Cullen, otherwise known as Speedo Mick, will reach the end of a 1,000-mile walk for charity that has been as punctuated with cheers and good wishes as it has bad weather.

As a lifelong Everton fan who walks in club-branded swimming trunks and scarf, the 55-year-old has arguably suffered enough, but he says the gruelling walk has been the greatest challenge of his life.

“I walked through Glastonbury during Storm Ciara and it was nearly blowing me knickers off, which wouldn’t have been a good sight for anyone,” he said. “The cold is really mentally challenging. I’m not really dressed for it, I’m basically walking through the dead of winter in a pair of shreddies.”

Along the way he has been treated like a hero, he received a £50,000 cheque on the road near Old Trafford in Manchester, was praised on BBC Breakfast and was treated to a hero’s welcome in his home city, where he will celebrate with a fundraising ball in March.

A few days ago a 75-year-old woman made her daughter drive 50 miles to give him a cuddle, and as he speaks to the Guardian a woman from the village he has just passed through arrives with a cup of hot tea, while a driver passes by tooting the car horn. “It’s heartwarming to think anyone can dedicate time to great causes,” said Jules Hayden from Whitemoor in Cornwall. “I just wanted to give him something to keep him warm.”

After his cup of tea, Cullen said: “It brings a little bit of light into people’s lives, doesn’t it? It makes people smile and that makes it all worth it. It’s more than just raising money, it’s spreading a lot of love.”

Cullen – who has become a well known figure in Liverpool thanks to frequent social media posts of him chatting and dancing along the route – started his trek from John o’Groats to Land’s End on 10 December and is now just over £15,000 pounds off hitting his donation target of £250,000.

speedomick (@speedomick) Thanks @steam_1000 for reminding me of this cracking bit of swivelling I did a few days ago. 🕺🏼🕺🏼🕺🏼🌪🌪🌪🥶🥶🥶 The Speedo song 🤪🤪🤪

Who loves ye Babeeeee 💙💙👣👣 Don’t forget to keep sharing and donating only £21k off the target! https://t.co/1thFo7tjYa pic.twitter.com/Wrg0P0RczI

After years of raising money for charity, including Everton in the Community – first by swimming the Channel, then by walking to France – Cullen has started his own charity, Leave the Light On, which will run community projects for disadvantaged people of all ages, with a focus on mental health and positivity.

The club he follows has shown him a lot of love in return. When Cullen got a calf injury he was taken to Everton’s training ground, Finch Farm, to meet the players and receive treatment. “His presence on a matchday is really unique in the Premier League and he is as popular with away fans as he is with home supporters,” said the former Everton player Ian Snodin. “Mick epitomises the positive and caring attitude that Evertonians and scousers have.”

It was the Channel swim that led him to develop his trademark look, he explained. “I thought there’s no way I’m putting a pair of Speedos on, it took me a year to not feel embarrassed in the swimming pool but I got over myself – and I’m glad I did, because I swam the Channel and by then I was used to them.”

So used to them, in fact, that he started visiting Goodison Park to watch Everton dressed only in his trunks and has since been welcomed in stadiums across the country. “The Speedos bring people together and it did that with fans from other clubs as well,” he said. “People respected what I was doing, and instead of being horrible banter it was nice and funny.”

He said he struggled with alcohol and drug addiction and mental health issues for many years, and was homeless for a time. He has been clean and sober for 18 years, but could only do that thanks to the help of others – so he wanted to spread his message of hope and endurance via the unconventional means of a bright blue pair of pants.

“My message to people is that there is always hope,” he said. “Hope lives in the darkest places, even when you don’t think it is there. All my thinking got me to a dark and lonely place, so my message to anyone else there who is suffering, and a lot of people are, is that there is hope and you can turn your life around. You can get your life back.”