When UKHSA did publish a methodology memo outlining the modelling behind the claim, on Dec 16, it revealed that the modelling had been abandoned because it was no longer correct to assume that the doubling rate of the variant would remain constant.
In the letter to UKHSA, Ed Humpherson, who is head of the Office for Statistics Regulation (OSR), said: “The Secretary of State … mentioned an estimate of the daily number of infections of Covid-19, which was initially also unsupported by data. This caused confusion and some speculation in the media, which distracts from the message the statistics are conveying.
“An explanation of the methodology used to arrive at the daily number of infections was published on 16 December. OSR has previously made clear its expectation that data and methods should be made equally available to all before any planned statement is made. Transparency of data used to inform decisions is vital to public understanding and public confidence.
“In this case, the delay between the use of the figure and the publication of the data was unsatisfactory.”
In the letter, dated Dec 17, Mr Humpherson said he understood that health officials were planning to ensure that in future “announcements of high importance such as this will be suitably supported by data, if not before, then as soon as possible afterwards”.
He added: “I appreciate the urgency of this particular situation meant that the statement used the most up-to-date data possible. But the general principles of transparency should still apply.”
Last month, The Telegraph revealed that Dame Jenny was the source of a contested claim by Mr Javid, the Health Secretary, that there was typically a 17-day lag between patients becoming infected and requiring hospitalisation.
Independent experts pointed to Office for National Statistics data, which suggested an average delay of nine or 10 days.
The claim by Mr Javid was seen as an attempt to strengthen the case for urgent new Covid restrictions, on the basis that the country could have been on the brink of a major spike in hospitalisations due to omicron.
Dame Jenny has claimed that omicron was “probably the most significant threat we’ve had since the start of the pandemic”.
