Clyde Best has recalled the day he received a chilling letter from a football supporter threatening to throw acid in his face.

The former West Ham United forward distinctly remembers being left cold when he opened the note, which was among the post brought into the team’s dressing room at Upton Park every Friday.

Best had been on the receiving end of some horrific racist abuse during the 1970-71 season and admits he was nervous about the prospect of running out on to the pitch the next day.

“When you’re a young player and you’re giving the best you can — and then to be given a letter like that, it’s mind-boggling,” Best, 65, told The Daily Mail.

“When I gave it to my boss [Ron Greenwood], I knew he was shocked. He had probably never experienced anything like that before. The good thing about the guys I played with, like Bobby [Moore], Geoff [Hurst], I think Ron would have told them and they came to my defence.

“They made sure that when we ran out, I was in a circle. And the police, they were fantastic. They made sure that, if it’s going to come, it’s going to have to go over the top of their heads.

“So they were putting themselves at risk. You have to be thankful to all those sorts of people, who had an interest in what I was doing. I tell people: ‘I couldn’t do it by myself’.”

Best has largely kept his counsel regarding the racial torment he suffered during his playing days. But he is in England promoting his autobiography The Acid Test, and is keen to tell his full story.

“Never before in my life had I experienced that,” said Best, who was guest for the day when West Ham beat Hull City 1-0 at the London Stadium on Saturday. “And you just had to be bigger than that. And you have to remember you’re not doing it for yourself. You’re doing it for other people after you.”

Yet eventually the repetitive drone of monkey chants made him angry. He remembers a game against Everton at Goodison Park.

Best said: “It got so bad and I said: ‘I’m tired of this crap.’ So I picked the ball up from halfway and I’m on a solo run. And I never forgot, this boy, Terry Darracott, was pulling on my shirt and my arm — and I dragged him all the way to the goalkeeper.

“As the goalkeeper came, I did a dummy and he went down and I just chipped it over the top of his head.

“Joe Royle [the former Everton striker] came up to me afterwards and said: ‘Clyde, that’s the best goal I’ve ever seen at Goodison Park’.

“But I was angry. Especially when you know you’re going out there and you’re doing your best and you’ve got one or two — I call them not so clever fans, who are just crazy — that more or less use that [abuse] to take out their frustrations on you.”

Best arrived in England as a 17-year-old at a time when significant migration from the West Indies had become a feature of English life.

He was not the first black player in England, but was one of the first prominent black terrace heroes and helped paved the way for the next generation such as Cyrille Regis, Brendon Batson and Garth Crooks.

“When you start off you don’t have any plans,” Best said. “You don’t have those thoughts in your mind. You just want to go about your life, do the best you can and have a good time and be the best person you possibly could be.

“But so many years later, you get the next generation, which put you up there on a pedestal, telling you that you’re a pioneer, you did this for me and that for me.

“And I thank my dad, because he always told me, when you’re playing on the field, you’re not playing for yourself, you’re playing for the guy who cleans the toilet, you’re playing for the guy who works a job where he’s not paid a lot of money, the guy who wants to be a professional. And that’s the way I went about my career.”

Best chooses to end his story on a positive. His book recounts how one Englishman, who had settled in Bermuda, contacted him. The man, a policeman, admitted to having been one of those fans who had racially abused him.

“He wrote me a letter and told me about what he used to do on the terraces,” Best says. “He apologised. It takes a man to admit something like that. He’s retired now. And he ended up marrying a black Bermudian girl. So what’s he going to say to his children! But he was young.

“I’ve learnt that you never judge a person by the colour of their skin. It’s stupid.”