However, he is unhappy at having had no prior knowledge of Robben’s recent visit to Old Trafford.

United have already bought Jaap Stam and Ruud van Nistelrooy from PSV, with the former since alleging in his autobiography that he had been tapped up by Ferguson.

Raaij told The Guardian: “United approached us some months ago about their interest in Arjen but then I heard that Robben was in Manchester last week and I didn’t know anything about that.

“There was absolutely no contact from any United delegate and we are unhappy that we did not know one of our players was visiting another club without our permission

“I have spoken to (United chief executive) David Gill since I learned of the visit and he was a little embarrassed and said that the initiative was taken by Robben’s parents.

“I have had good relations with Manchester United in the past over the Ruud van Nistelrooy and Jaap Stam transfers but bad relations with Ferguson.

“I recognise here exactly the same actions as when he approached them both. It is Ferguson’s way of doing business but it is not my way.

“You can look back and see similarities to what happened with Stam and Van Nistelrooy. It just seems that, with Ferguson, a leopard never loses its spots.”

Raaij added that any move is highly unlikely to happen before next summer and warned he would not sell Robben cheaply.

When a £5m (€7.14m) fee was mentioned, he said: “For that money they can get a shirt from Robben with his signature on it, nothing more.

“I will not tell you what cards I have but that figure is a laugh.”

Robben said of his trip to Manchester: “My first impression of Ferguson is that he is a nice and good man to deal with.

“What I have seen in Manchester looked good, especially Old Trafford is very impressive. It’s now up to the clubs and I can’t do anything more for the time being.”