Yakubu became Everton's record transfer, costing �11.25m

The Nigerian striker moved to the Liverpool-based side from Teesside in the close season for a fee of �11.25m.

In the wake of the move Boro chairman Steve Gibson said the 24-year-old had "switched off" during last season.

Yakubu, though, retorted: "It is unfair to say that, I played for Middlesbrough for two years and scored many goals."

"It is ridiculous for them to say that I switched off.

I don't have anything against the chairman or the club and so I was very disappointed for him to say things like that Ayegbeni Yakubu

"Before the season started they were saying they did not want to sell me and that they were happy with me," Yakubu added.

"But at the end of the transfer window they decided to sell me and I wanted to leave anyway.

"I don't have anything against the chairman or the club and so I was very disappointed for him to say things like that.

"I was not happy and I wanted to join a club with more ambition than Middlesbrough.

"They never said I switched off when I left Portsmouth, they all loved me and I would never say anything abusive about Portsmouth.

"So for Middlesbrough to come out and say things like that in the newspaper is not good, you don't do that.

"I think they have to grow up."