Schmeichel is often rewarded with a gravy bone

Eriksson said he first noticed the behaviour when goalkeeper Kasper Schmeichel returned a water bottle that had be thrown to him.

"One of the coaches threw the bottle but it went over Kasper's head. He chased after it, picked it up and brought it back, clearly very keen for us to throw it again.

"We quickly moved on to sticks and then tennis balls."

He added: "Sometimes I just pretend to throw the stick. Danny Mills will run off but stop after a few yards and turn around and look at me as if to say, 'where's it gone?'"

The players are also transfixed by colours, unusual shapes and bright lights, the manager said.

"We were in the changing room after a training session and I noticed that quite a few of the boys were distracted by a strange, fast-moving light on the wall.

"I then realised it was just the reflection from my watch. Whenever I moved my wrist, their heads would quickly follow. Now I use a torch."

Eriksson added: "They love to sit in front of the television when Strictly Come Dancing is on.

"They are fascinated by the movement, and whenever Bruce Forsyth is on screen Rolando Bianchi will just crouch down and howl."