The Treasury Select Committee published its review of the RDR last Saturday and called for the implementation to be delayed by a further year.

The FSA then responded almost immediately, rejecting this proposal on the grounds that firms had already had long enough to prepare for implementation.

Now Mr Tyrie has written to FSA chief executive Hector Sants to criticise his actions.

In his letter Mr Tyrie writes: “Last Thursday the FSA circulated an embargoed response to our RDR report, rejecting in a peremptory manner our recommendation of a one year delay to the RDR’s introduction. This was issued within hours of the embargoed copies of our own Report being distributed.

“The Committee has discussed this. We deprecate the Authority’s decision. It was precipitate, giving the impression that no adequate consideration had been given to the arguments for the delay we recommend. This is unacceptable.”

The decision has also been criticised by other members of the Select Committee.

But financial firms agree with the FSA’s decision and feel that a delay would be a bad idea.

A spokesman for The Institute of Financial Planning said: “We support the FSA’s rejection of the recommendation from MPs. “The process has been underway since 2007 and we believe that the goal of bringing about greater professionalism and clarity for consumers is too important to start moving the goalposts now.”

Kay Blair, vice-chairman of the Financial Services Consumer Panel, said: “Four years have already passed since the FSA set out the overall objectives of the RDR. Further delay will only risk harm to consumers as the effects of poor financial advice can last a lifetime.”