In an intervention that will do nothing to soothe a tense relationship with his former employers, Yakubu Ayegbeni has accused Middlesbrough of lacking ambition. The Nigeria striker, who swapped Teesside for Everton last summer, was jeered mercilessly on his return to the Riverside Stadium on Tuesday, but he is adamant that his decision to leave was justified.

With Gareth Southgate’s team labouring in the Barclays Premier League and Everton in the top six, there would appear to be merit in Yakubu’s argument. Yet for all their difficulties, Southgate and Steve Gibson, the club chairman, are determined to propel Middlesbrough back up the table, albeit in a manner that encourages greater self-sufficiency.

In the light of Yakubu’s departure to Everton for £11.25 million and Mark Viduka’s free transfer to Newcastle United, Southgate targeted Peter Crouch and Jermain Defoe as potential replacements. Middlesbrough were told, however, that the former would quit Liverpool only for another club playing Champions League football and that the latter was desperate to stay in London.

There is an eagerness at Middlesbrough not to stifle the development of their talented academy graduates by boosting their first-team squad with substandard signings, even if that policy has caused Southgate short-term difficulties. The manager, whose squad has been hampered by injuries, will be intrigued by Yakubu’s comments, given the striker’s questionable attitude during his final months at the club.

“I wanted to move to a club which had ambition,” Yakubu, who scored 25 league goals in 73 appearances for Middlesbrough, said after Everton’s 2-0 victory at the Riverside. “I think at the moment Everton have ambition. They want to play in Europe and finish in the first six. I am happy. My football has been good and I have no regrets. I wish Boro the best of luck.

“Before I left Portsmouth, I looked at Middlesbrough and saw they had ambition, but I don’t think the ambition is there any more. I decided to go to Everton because they had more ambition. They are fighting for trophies, they want to finish in the top six and get into Europe.

“At the moment, with no disrespect to the players, Middlesbrough are not that ambitious and that is why I had to leave. I would not say anything bad about their players, but I just wanted to play for a club that was in Europe and I am enjoying my football at Everton.

“Middlesbrough – the club – has changed a bit, but I never regretted playing for Boro at all. I enjoyed my time there, but it was definitely the right time for me to move. I made the right decision. We are chasing a trophy in the Carling Cup and if we can win something, that would be a great season for me and the club.”

However, Yakubu does not believe that Middlesbrough will be drawn into a relegation battle. “They will have to be patient with him [Southgate],” he said. “This is his second season and he has to be given the time to turn the club around. If he can do that, it would be a great achievement for him. With the young players they have and the experienced players like Julio Arca and George Boateng, they should be able to stay in the Premier League.”

Yakubu was not surprised to be taunted with abusive chants by Middlesbrough supporters. “It is a great feeling to be back where I played for a few years and the fact that we got the three points makes me very pleased,” he said. “It is football, so I expected that kind of reception. I believe I made the right decision to go. It is disappointing when you play for a club, then you leave and come back and the reception is bad, but you have to cope with it as a footballer and accept it.”