SNP ministers have admitted the British safety standard cited for their £8m baby box scheme does not apply specifically to the cardboard crib given to parents.

The heavy-duty material was “not tested at the request of the client”, according to the test certificate, which focused on safe edges, dimensions and load bearing.

With a standard for cardboard baby boxes yet to be developed, an existing standard applied to furniture cribs was tested against and cited by the Scottish government instead.

Dr Peter Blair, chair of the International Society for the Study and Prevention of Perinatal and Infant Death (Ipsid), said the government was pushing its advice “too far at the moment”.

Dr Blair also raised more general safety fears about the boxes, a Finnish idea rolled out across Scotland since August, in a recent memo to the Scottish Government.

The free boxes include a mattress, blankets, thermometers, clothes and books, with the box itself promoted as a “safe sleep space for babies”.

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However the Guardian newspaper reported Dr Blair, of Bristol University’s medical school, said there was no evidence they were safe or reduced cot deaths.

He also urged the government to stop claiming they were safe spaces for regular use.

Part of a panel advising Scottish ministers on the project, he stressed he was not advocating that parents stop using the boxes for their newborns.

However he said the government “shouldn’t be advocating infants sleep in these boxes unless there isn’t anything else available”.

He said: “I’m not saying don’t use the baby box, I’m just saying that you’ve got to be careful with the advice of how much you can promote it as a safe sleeping space.

“I think there’s possibilities there but there’s much room for manoeuvre and they’re pushing it too far at the moment.”

He also sent the government a draft statement backed by the board of Ipsid about the boxes.

It repeats many of the points made by Ipsid member the Lullaby Trust last year, such as a lack of evidence that boxes reduce mortality, something the Scottish Government accepts.

The Scottish Government’s Parent Club website carries a Q&A about the baby boxes.

Under the section “Does Scotland’s baby box meet industry safety standards?” it says: “Yes. We know it’s important that parents feel reassured about the Baby Box and its contents.

“That’s why we have worked with British Safety Standards to ensure the box meets all safety requirements including testing of construction, specification, load and stability.

“The box is marked with the European Standard on Cribs and Cradles for Domestic use BS EN 1130 accreditation and safety instructions and labelling can be found inside.”

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However the British Standards Institute, which oversees product safety regulations, told the Guardian there was no specific standard for baby boxes, though one was being developed.

It said: “At present there is no standard that covers baby boxes.

“There may be some clauses of the BS EN 1130 furniture, cribs and cradles for domestic use series that could be applicable to baby boxes, but BS EN 1130 is a furniture standard and not intended for cardboard baby boxes.”

Tory health spokesman Miles Briggs said: “There are some extremely serious questions for the SNP Government to answer here. Parents have been told time and again by Nicola Sturgeon and her ministers that baby boxes are safe.

“Now we learn that a senior expert has raised questions about the evidence base for that in private, and that there are doubts over whether the boxes have the full safety accreditation.

"Why has is taken only now for these concerns to be raised in public? And why, initially at least, did the Scottish Government fail to take Mr Blair's concerns on board?

"If parents are to have faith in these boxes, then we need to see complete transparency from the SNP. This is not a public relations exercise - it is about child safety."

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Labour MSP Mary Fee added: “This is incredibly serious. The Scottish government need to ensure these boxes are safe as a matter of urgency. Labour supports the baby box, and have in the past suggested items that may be of greater use to new mums,but the safety of newborns has to be absolutely paramount.

"The suggestion that the Scottish government may be claiming a level of safety accreditation that the boxes do not have is astonishing.This is about safety, not spin."

A Scottish Government spokesperson said: “There is no evidence to suggest the baby box is unsafe and we are in ongoing discussions with Peter Blair about his concerns. The Baby Box meets British safety standards and was awarded British Safety Standard accreditation as a crib for domestic use - the first non-commercial box in the world to do so. We will ensure that Scotland’s Baby Box complies with the new standard once it is developed.

“As the material issued with the Baby Box makes clear, the Baby Box – and its associated bedding – is intended to offer a safe sleeping place when used in accordance with other safe sleeping practices.”

READ MORE: Parents snub the box part of SNP's baby box

Last year research commissioned by ministers revealed the cardboard container was the least popular element of the baby box package, with 45 per cent of new parents saying they did not intend to use it as a crib. The other elements were almost universally popular.