The Premiership club were fuming when Ramon Calderon, the Real president, claimed Roman Abramovich could be dangerous for the game due to the amount of money he has ploughed into the Stamford Bridge side.

Calderon believes the two-time Premiership champions are over-inflating transfer fees for other European clubs and expressed concern at the huge financial loss they have made since Abramovich took full control of the club.

“I think it’s a problem, it’s putting the prices very high,” he said. “He is paying a lot of money for players, but we have to compete with it. In Abramovich’s case, he admitted to having lost 220million euros [£150million] last season. For me, it’s very dangerous.”

Calderon is also worried what would happen were the Russian to walk away from Stamford Bridge, warning: “You don’t know how long those people are going to stay in soccer. If somebody decides to leave, it’s going to be a problem.”

Chelsea hit back by reiterating Abramovic's commitment to the club. “I would not doubt Roman Abramovich’s commitment, not just to Chelsea but to football generally,” said director of communications Simon Greenberg.

“The money that’s been spent has been invested into football, the majority of it. A very small amount of his current investment went on purchasing the club. The rest of it has gone into football and filtered down through football.

“Although we made a substantial loss last year, there were a number of one-off payments that won’t be repeated this year and our auditors, who are one of the leading auditing firms in the world, would never have signed off our accounts [otherwise].

“We run ourselves as much as we can as a plc. We are completely transparent about our accounts - which is something that cannot be said for many of the top European clubs including, I would say, Real Madrid.”

Greenberg also insists Chelsea are not artificially inflating prices in the transfer market and believes it is they who often suffer when negotiating to buy players.

“It’s an open market. People can pay as much as they want to pay,” he said.

“We feel sometimes we have to pay a bit more because we are Chelsea. Clubs are not prepared to sell at a particular price because they feel that they can get more from Chelsea and therefore they play one off against another.”

He added: “We have been "involved" in a number of transfers we weren’t actually involved in because clubs have put in Chelsea’s name saying "Chelsea are bidding", and we’ve got nothing to do with that.

“They try to drive the price up that way. But I don’t think we artificially inflate any prices at all. We pay what we believe is a fair price.”

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