Today is the final day of the cricket county championship, with Essex and Somerset playing each other in the title decider. Whoever wins, the match will mark the end of an era: it’s Marcus Trescothick’s last match for Somerset after 27 years at the club.

As ever with cricket, the stats tell a story – 94 centuries and almost 40,000 runs – but only part of the story too. They don’t tell you how much everyone in Taunton loves him, how the young players idolise him, how he happily passes on all the wisdom he’s accrued over the years.

He came to my kids’ school to open the sports hall and was wonderful with a bunch of bright-eyed boys and girls who queued up to bowl at him. I’ve seen him on the touchline at Chard on a Sunday morning as our daughters played hockey, and he’s just another dad clutching a takeaway coffee and happy that his child is doing something they love.

If you were an England fan, he was one of the best: 76 Tests at an average of just under 44. Tres was an opener, the hardest position to bat: the bowlers are fresh and the ball is hard. Opening batsman is no place for shrinking violets. His fellow opener on his debut was Michael Atherton. It was his 100th Test. Atherton would always ask his partner whether or not they wanted to take first ball. Some desperately wanted to, others equally desperately didn’t want to. Some chopped and changed their minds. Tres did none of these. He shrugged and said he didn’t mind and right there Atherton knew he was the real deal.

Tres scored 14 Test centuries for England, but perhaps his best innings was one which fell just short of making that number 15. It was the opening day of the second Ashes Test at Edgbaston in 2005. England had lost the first one heavily, and couldn’t afford another defeat so early in the rubber. Australia chose, unwisely, to bowl first, and Tres climbed into them. He scored 90 off 102 balls, all with his deceptively simple approach to batting which divided balls into three categories: the ones he could leave, the ones he could block and the ones he could biff. It was a statement of intent – we’re not going to be cowed any more – which rippled all the way through the team, and in doing so helped set up not just the greatest Test of modern times but also the greatest series.

But most of all, of course, Tres will be remembered for something far more important than leather on willow. When he came home suddenly from the Ashes tour in 2006-7, all kinds of rumours were swirling around – that he had a mystery virus, that a team-mate was having an affair with his wife, and so on. In fact, he was suffering from depression. It was the kind of thing that people didn’t like to talk about, especially if they were men and even more especially if they were alpha high-achieving show-no-weakness males.

Tres decided that no, he was going to talk about it. He wrote a brilliant, searing memoir called Coming back to me which won the William Hill Sports Book of the Year prize and pulled no punches in its descriptions of the toll the illness had taken on him: the “shiver” he felt just before it settled on him, the time he was lying face down on the floor of Dixon’s in Heathrow unable to get up.

A decade or so on, sportsmen are much more inclined to admit weakness, and no-one has done more to help that than Tres. It was he who first opened the door, he who showed that this was nothing to be ashamed of. I have seen it first-hand, not just while writing Open side with Sam Warburton but also Unconquerable with the Invictus Games competitors. Before Tres’ book, they wouldn’t have opened their souls to me, I wouldn’t have asked them to, and the publishers wouldn’t have been interested.

“Cricket has been my life,” Tres said. “It’s always been special to me and it will be for ever, but I know that the mental health side of things has been pivotal to my career, and may be remembered after my cricketing achievements have been forgotten. I’m not a medical expert, obviously, but I have experience and I can talk about coping mechanisms and what has worked for me. If that helps people then great.”

It has helped more people than he knows. For every one who had written to thank him – and there have been plenty – there must be many more who have benefitted in silence. “Oh, he’s the best,” said Somerset chief operating officer Sally Donoghue. “Legend is an overused word, but he is an absolute legend.”

He is indeed, in every way.

Boris Starling is an award-winning author, screenwriter and journalist whose works include Sunday Times and New York Times bestsellers.