The Exchange also said it will take no further action over the Government sale of shares in the generators, National Power and PowerGen, which was hit by a statement on prices by Professor Stephen Littlechild, the electricity watchdog.
The Government was aware that there might be a statement but decided to proceed. The statement wiped pounds 3bn from the value of shares in the sector the day after dealings began.
A report from the Treasury, published on Thursday, said that the department was not guilty of improper action in allowing the sale to proceed. It showed how the regulator prevaricated over whether to make the announcement and appears to point the finger of blame in his direction. But a spokeswoman for Professor Littlechild yesterday denied any wrongdoing on his part and said there was no pressure for him to resign.
"The report from the Treasury does not put the blame on anyone," she said. "We are saying we kept everyone informed all the way along. There was no question of his changing his mind. It was just one of making the final decision, which he did on the Monday."
The Treasury report also calls for regulators to take advice on stock market matters, including the effect of their actions and the way they are announced.
Michael Lawrence, chief executive of the Stock Exchange, had already asked regulators for a meeting concerning price-sensitive information. He said yesterday in a letter to the Treasury that all relevant information from both the public and private sectors should be available to the market before share offerings to the public.
Ian Byatt, the water industry regulator, said: "In my view, regulators should work in a proper way with the Government, but with regard to their independence."