Ajax technical director Martin van Geel has suggested the Premier League club did not conduct themselves in the proper manner over their bid to land ten Cate.

Van Geel claimed that Chelsea contacted Henk behind their back and although the English club have not, as yet, made any official comment about Ten Cate's imminent arrival, negotiations are ongoing.

Chelsea are understood to be disappointed by Van Geel's remarks especially in the light of the compensation figure which was quickly agreed between the two parties.

Van Geel told new talk TV station Het Gesprek: "Chelsea have contacted Henk behind our backs and without our knowledge he went to London to talk to them. Henk informed us last Tuesday about this. I don't think that is right. For us this all comes on a very bad moment; if it was up to us we would have ended the season with Henk."

But Van Geel was generally supportive of Ten Cate's efforts as coach at Ajax, even though they are out of the Champions League and the UEFA Cup.

He added: "We did not do well internationally, but Henk did bring in passion. Ajax play better than before, that's a fact. We scored more goals and conceded less goals than before."

While Tottenham's Martin Jol has been linked as a possible replacement, the head of youth Adrie Koster has been appointed as interim coach.

Former RKC Waalwijk boss Koster will move up from his role as coach of Jong Ajax to take charge of the senior side, with Ten Cate's right-hand men, Alfons Groenendijk and Hennie Spijkerman, staying on his assistants.

Meanwhile, England midfielder Frank Lampard insists Chelsea's performance in their 1-0 win over Bolton on Sunday was still short of the standard required.

Lampard, who returned to the first team at the Reebok after finally recovering from a thigh injury, insists there is still much work to do before they can start to talk about being back to their best.

The victory was their first in the league - and under new coach Avram Grant - since Lampard scored the winner against Portsmouth back in August. Now the midfielder says they need a run of good results to get them back in the challenging pack at the top of the table.

Lampard declared: "There's a long way to go, we need to be up there like the last three seasons. We need to be challenging for the league rather than talking about being in eighth place or sixth place. It's very important we win, and then talk about turning corners.

"We need to stick a run of wins together, five, six or seven, and hope other teams slip up. We've been in positions before where we're up there and you always fear teams coming from behind and putting a run together and we have to be that team."