The First Minister has been accused of "seriously twisting" Covid infections data from the Office of National Statistics and reported to the UK statistics authority.
Nicola Sturgeon claimed this week the figures showed that infections in England were "20 per cent higher" than in Scotland.
However, the statement has since been challenged by the opposition. MSPs outlined that the same data set suggests that last week, around one in 20 members of the public had covid in both countries, the Daily Record reports.
Willie Rennie has now written a letter of complaint asking stats experts to verify the First Minister's claims.
The former Scottish Lib Dems leader warned the figures "may have been seriously twisted".
Speaking at First Minister's Questions on Thursday, Sturgeon used the 20 per cent higher figure to justify her Government's more cautious response to the Omicron variant.
Tory leader Douglas Ross had accused her of being too "gung-ho" in reintroducing restrictions such as social distancing in pubs over the festive season - a measure not used in England.
Sturgeon hit back: "In terms of the ONS figures this week, infection levels in England right now are over 20 per cent higher than in Scotland.
"I don't think it's a competition, but if Douglas Ross wants to make these comparisons, then they are the comparisons, there is the data."
In a letter sent today, Rennie said: "ONS figures state that one in 20 people were infected in both Scotland and England in the week ending 15 January.
"They also state that the estimated average percentage of the population that had covid in Scotland was 4.49 per cent compared to 5.47 per cent – a difference of less than one per cent.
"The public have a right to always expect the Scottish Government's interpretation of data to be robust.
"This is even more important when that data is being used to justify and substantiate restrictions on their liberty and freedoms under the use of emergency powers.
"Parliament has granted powers to ministers that would not be countenanced in any other circumstances, so scrutiny of how they are used is essential.
"Public confidence in these statistics must not be put at risk. There must be no bias, spin or manipulation. However, I am concerned that these statistics may have been seriously twisted.
"I would be grateful if you could advise on whether the ONS statistics should have been portrayed in this way and whether the First Minister should continue to report statistics in this manner."
The Scottish Government has been contacted for comment.
