Monitor has attempted to block Unison's judicial review by launching a three-month consultation into its interpretation of the foundation trust private patient income cap.

Executive chair Bill Moyes said he would use the consultation to determine whether Monitor's interpretation of the cap, which allows foundation trusts to expand their private work using an arm's-length organisation, was correct. He said he hoped this would mean the High Court would refuse to proceed with Unison's judicial review.

Mr Moyes denied that the move meant he lacked confidence in Monitor's current interpretation of the Health and Social Care Act 2003.

Unison head of health Karen Jennings said: "This is a question of law, and there seems to Unison to be little point in consulting about questions of law."

However, Mr Moyes indicated that Monitor may be preparing to challenge the authority of Parliament to determine what the law is.

Opponents of the way Monitor has interpreted the cap believe their case is strengthened by statements made by the former health minister John Hutton during the debate in 2003 surrounding the establishment of foundation trusts. Contrary to Monitor's practice, Mr Hutton said that trusts should not be able to use joint ventures or space-leasing arrangements to "circumvent" the cap.

Mr Moyes said Monitor's responsibilities had been open to interpretation. "Although John Hutton made statements in Parliament, he didn't take the step of ensuring the legislation precisely reflected these. There are other things we have to take into account and the legislation gives us the responsibility to do that."

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