The Independent reported on Tuesday that the agriculture committee had formally decided to investigate controversial government plans to curb the sale of Vitamin B6.
But at a private meeting of the committee on Tuesday morning, that decision was re-opened by Peter Luff, the Conservative chairman. The Independent has been told that some of the Labour MPs on the committee protested that the inquiry decision had been taken in their absence, and the question is to be discussed again next Tuesday.
Mr Luff told the PA news agency on Tuesday night: "We have not taken a decision yet, but it's under consideration by the committee."
In fact, a decision had been taken, but it had been decided to reconsider it following the Labour protest.
Any hint of pressure from the whips is bound to backfire, and it is now expected that the inquiry will be given the go-ahead next week. If the Labour majority was mobilised to vote down the inquiry, it is possible that a formal complaint would be made about whips' pressure to the Commons Committee on Standards and Privileges.
The last time a government whip put pressure on a Commons select committee was in October 1994, when David Willetts, the former Tory whip, was alleged to have brought improper pressure to bear on an investigation into Neil Hamilton and the cash-for-questions affair. In December 1996, Mr Willetts was censured for discussing the work of the committee with its chairman.
Under government proposals, over-the-counter B6 sales of more than 10 milligrams a day will be restricted to pharmacies and any doses over 50mg a day will have to be prescribed by a doctor.
Marion Allen, chairwoman of the National Association of Health Stores, said yesterday that the agriculture committee should resist party pressure to abandon its inquiry.
"The inquiry would examine why Vitamin B6, taken by millions of Britons in doses up to 200mg daily, is under threat," she said.
"Since the Government announced proposals to restrict its free sale to just 10mg, MPs have received more than 100,000 protest letters and a report from 200 doctors and scientists rejecting the decision as 'a wholly inadequate consideration of the scientific data'."
A Ministry of Agriculture spokesman said ministers had received 11,500 protest letters, and 1,300 letters passed on by MPs.
Many of the letters have been sent in standard format, which includes the sentence, "Along with many thousands of other consumers, I take 100mg of Vitamin B6 on a daily basis to help maintain my general health and to ease the discomfort of pre-menstrual tension." Many such letters, it was said, had been signed by men.
The ministry said the Government was acting on advice from the Committee on Toxicity, that large doses could damage people's health. The spokesman said the maximum daily dose permitted in other European Union member states was 6mg - as was the case in Germany.