Campbell has pinpointed a lack of explosiveness in the 28-year-old, which could be the missing piece of the jigsaw within his game after Chelsea manager Rafa Benitez talked about Torres and how he has become much slower since moving from Liverpool two years ago.

The 39-year-old, who now works specifically as a speed coach for rugby and football players, believes it would not be a lengthy process to restore Torres' pace.

Campbell told the Telegraph: "Fernando had real pace. He has to train in a way that suits him. You have to work in the gym on strength. Maybe he needs to do that again.

"It's something that is best done in pre-season but I think Fernando just needs two weeks when he hasn't got to worry about playing on the Saturday and just put in a nice two-week training program that I think would definitely bring the majority of his speed back.

"I'm sure I could fix him. It doesn't have to be a lengthy process because these guys are already extremely fit. That's the great thing about working with footballers and rugby players. You're not having to worry about the base fitness so you just go in and teach the raw speed.

"In the case of Fernando, I think he would also probably need to do a bit of weightlifting as well as the running and the speed drills to put some power back into his muscles. That's why sprinters lift weights, to gain that explosive speed and power."

Campbell was invited to help Torres out by Chelsea medical director Dr Bryan English during Andre Villas-Boas' reign, but the training ended when the former manager was sacked.

"I only did about two or three sessions with Fernando but I could see his confidence coming back," Campbell said.

"The biggest problem is that when you lose your speed you're unable to do what you used to be able to do, and so then you start trying harder and harder. But that can be counterproductive.

"If you want to be quick, there's an element of relaxation that's involved. You've only got to look at Gareth Bale. He runs at high speed but it's all relaxed and there's no tension in him.

"The problem with someone like Fernando Torres is that the harder he tries to find that speed, his efforts are actually detrimental."