Chelsea scout Piet de Visser says he repeatedly urged the Blues to sign current Tottenham Hotspur midfielder Mousa Dembele, describing the Belgium international as a "world class player."

Dembele, 28, joined Fulham from Dutch club AZ in 2010 and was initially deployed as a forward following his arrival in the Premier League. After dropping back into a midfield role he was signed by Tottenham in 2012 and, despite uncertainty over his future in north London last season, has evolved into an integral member of Mauricio Pochettino's side.

De Visser explained in an interview with Het Laatste Nieuws that he repeatedly urged Chelsea to sign the player, only to be ignored on each occasion.

"I fell in love with Mousa Dembele during the 2008 Olympics. He's a world-class player, but they have often played him out of position," he said. "He's not a striker or a second striker, not even a No.10. He's at his best as a central midfielder, as a No.8.

"He will never score 15 goals in a season, but he has a high work rate, a strong body and an excellent passing game. He's an all-rounder. Somebody with power, technique and stamina.

"I've often advised Chelsea to sign him, but other scouts and managers weren't convinced. They didn't see what I saw in him.

"After a while I started thinking: 'Am I crazy? Why can't anyone see it?"

De Visser has been critical of some of Chelsea's dismissals of his recommendations, having previously urged the club to hold onto Kevin de Bruyne, now starring at Manchester City after leaving Stamford Bridge in January 2014.

"I was angry with Mourinho when De Bruyne left Chelsea. We talked about it. Then he would say, 'Piet, I find it a shame too, but the boy wants to leave. He doesn't want to train under me any more.

"I told him: 'Yes, the boy wants to play. He is ready for it.' I tried to convince him on Kevin's qualities, but then Mourinho repeated: 'Piet, he doesn't want to train.' I went to see a training session, Kevin was the best player on the pitch."