"We should be euphoric, not depressed about the challenges of contract certainty and treating clients fairly," said Willis group chief executive Joe Plumeri.

Addressing the Chartered Insurance Institute's president's dinner, tough talking Plumeri said that insurers and brokers must provide details of deals up front.

"When a banker makes a loan, the person getting the money knows exactly how much they are getting and what the rate is. I can't think of any other complex industry like ours where parties shake hands one day and then sort out the details in the days, weeks and months ahead," Plumeri said.

On Spitzer, he said: "There is no question that clients should know how much money we make but disclosure is two-way and we need to tell them what we are giving them."