Earlier on Monday, Premier Rugby bosses could not agree with their First Division counterparts on the promotion issue, forcing RFU Chief Executive Francis Baron to decide the outcome, opting for the automatic 'one up, one down' system to continue, rather than have a play-off between the Premiership's bottom side and the Division One champions.
In a statement, the clubs said they were "extremely disappointed" with the outcome.
"Premier Rugby believes that this decision is not in the interests of the professional game in England and will actually have a considerable, damaging effect on the agreed objectives of the England national team and 12 professional clubs, as it does not encourage nor enable the professional clubs to plan beyond 12 months in any aspect of their business."
They pointed out that the prospect of automatic relegation could prevent investment in stadia, threaten the partnership between clubs and country, prevent investment in community schemes and did not allow an annual test to ensure the 12 best clubs in England were are playing in the Premiership.
The statement also said the decision was "likely to have a damaging effect on England's chances of winning the Rugby World Cup in 2007."
It concluded: "Premier Rugby feels the decision is a massive blow to the future of the professional game in this country and that once again, English sport has been let down in ensuring it has the right tools to perform at the highest level on the world stage."