Billy Nelson has described as “insulting” Lewis Crocker’s decision to replace him as his trainer with Huzaifah Iqbal.

The Northern Irishman won the vacant IBF welterweight title in his past fight, September’s rematch with Paddy Donovan, and on the eve of securing the date, location and opponent for his first title defence has separated from Nelson, the trainer who led him to his title and under whom he remained undefeated.

Crocker, 28, is expected to next fight his former opponent, fellow Briton Conah Walker, in a rematch, but regardless of the identity of his opponent he will prepare under Iqbal at the experienced Adam Booth’s gym and therefore relocate from Glasgow, Scotland to London.

Nelson previously guided his fellow Scotsman Ricky Burns to a version of the world lightweight title, and he told BoxingScene: “I’m disappointed that [Crocker] thinks he needs a change. He said he needs a change. I’ve also heard that he thought I’ve took him as far as I could, which I find quite insulting, actually. I’ve been involved with two world champions that have had 10 world-title fights. 

“A boxer’s gotta make a decision – what they think’s right for them. I don’t think it’s right. Especially when you consider the coach he’s went to hasn’t done a fraction of what I’ve done, and that’s no disrespect to that coach.

“It’s a guy called ‘H’, at Adam Booth’s gym. The thing is, he was at Adam Booth’s gym before he came to me, and he left it to come to me. We’ve looked after him in Glasgow, way beyond any other fighter – way beyond. As soon as he won a world title he fucked off [laughs]. As I’m finding out from the boxing fraternity, people don’t think it’s right.

“Jamie [Conlan, Crocker’s manager] told me initially, and then Lewis told me and I said ‘He’s went in the changing room saying that I changed his life…’. How I done everything for him when he came to Scotland, to being replaced. He’s either being two-faced, or somebody’s been in his ear.”

Nelson was then asked about the extent to which the development came as a surprise, and he responded: “It wasn’t a surprise because I knew he was down, four weeks before I was told, for two weeks training, so I knew he was down there. But in that four weeks, from his manager, I was getting asked about Jack Catterall, [Conah] Walker, [Devin] Haney. Everybody knew, including myself, what was happening, but I just didn’t let on to them.”