The public health watchdog is in danger of becoming a “nanny state monster” as it increasingly makes pronouncements that encroach on other areas of public policy, an MP has claimed.

Tory Philip Davies said the National Institute for Health and Clinical Excellence (NICE) should concentrate on assessing the cost effectiveness of new drugs and stay away from proposing “ridiculous measures”.

He was speaking as the watchdog today called for all pregnant mothers to be given a carbon monoxide test to see whether they smoke so they can get the appropriate advice for quitting.

Last week it said there should be good quality lessons in sex and relationships for all pupils from primary school upwards, although the education had to be “sensitive to diverse cultural, faith and family perspectives”.

Commons Leader Sir George Young said it was important public bodies did not engage in “mission creep” and move into policy areas that were the responsibility of others.

During questions on future Commons business, Mr Davies (Shipley) asked: “Can we have a topical debate on the remit and membership of NICE? It is rapidly in danger of becoming a nanny state monster.

Sir George replied: “It is important that any public body should not engage in mission creep and start encroaching on the responsibilities of other organisations, such as school governing bodies or indeed parents.”

A spokeswoman for NICE said: “All the work that NICE does is referred to us by the Department of Health.

“All of the pieces of guidance that have been referred to, we have been asked to produce by the department.

A Department of Health spokesman said: “Since 2005, Nice has been responsible for producing public health guidance at the request of the Department of Health.

“NICE’s recently published guidance reflects topics raised by the previous government, and we will now work with Nice to ensure that its public health work programme is fully aligned with the priorities of the coalition.”