The Department for Education's failure to publish regional school Covid attendance data this term has "undermined" schools' ability to respond to the crisis, leaders in the North have warned.
The government has been repeatedly asked to publish data giving a breakdown of attendance in different local authority areas as the coronavirus crisis has escalated.
It produced snapshot figures for one day in October and has now announced plans to publish more data on December 15, following requests for this information from Labour's shadow schools minister Wes Streeting.
But Frank Norris, education adviser at the Northern Powerhouse Partnership warned that this was "too little too late."
And Mr Streeting said that failing to produce regular data until now has hidden the reality of the educational inequality Covid disruption has caused.
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The concerns have been raised as the DfE announced that an expert group tasked with solving how next year's GCSE and A level exam grades will take into account differential Covid disruption will not report until the Spring.
Mr Norris told Tes that schools and academy trustees have needed this attendance data regularly throughout the term to understand the risks they have face from Covid disruption in their area.
And he warned that without this information the sector does not know in proper detail which areas are now being hardest hit.
'Either attendance is important or it is not'
He said: "The Department for Education has this data and given that we are told that children's attendance in schools is all important it is surprising that they have not published it. Either attendance is important or it is not.
"And this would have told us exactly what has been going on and how badly affected different areas of the country have been.
"The lack of this information for two months has undermined trustees' ability to make decisions for their schools about how and when to stay open and to plan for the risk they might be facing from Covid in their area.”
Mr Streeting said: “There is no good reason why this data hasn't been published already. We need an accurate picture about what's really happening and we need it now.
"The government's failure to support schools to keep pupils learning risks reinforcing the North-South divide in our country and widening the gap between pupils from the most and least disadvantaged backgrounds."
Mr Streeting urged the DfE to publish the data now and an action plan to address this serious educational inequality.
Analysis by Tes has shown a regional imbalance in the impact of Covid disruption in schools.
An investigation from data from local authorities across the nine regions of England shows that two thirds of the hardest hit areas were in the North of England during the first two months of term.
Data showed six authorities where 75 per cent or more state schools had Covid cases of which four were in the North.
In October figures, produced by the DfE in response to a parliamentary question, showed that on 15 October, 17 out of the 23 local authorities where secondary school attendance had been below 80 per cent were in the North of England.
Mr Norris said that the lack of data since then meant schools don't know whether other parts of the country were now being hardest hit.
He added: “Sharing the data of which schools have been hardest hit by Covid would allow schools in different parts of the country to learn from each other. Publishing the data at the end of term is too late for it to be useful."
Mr Streeting asked to the DfE to publish the number and proportion of pupils not attending school as a result of testing positive for covid-19; being suspected of having contracted the covid-19 virus; self-isolating having had a potential contact with a confirmed case of covid-19 or as a result of their school having been closed for reasons relating to the covid-19 outbreak.
And he asked for this to be broken down for all state-funded primaries, secondaries and special schools in each region and local authority area.
In response Mr Gibb said: "The department intends to publish regional and local authority level data on 15 December. This data will be included as part of the publication: ‘Attendance in education and early years settings during the coronavirus (Covid 19) outbreak’."
He said the the frequency of this publication will be reviewed in the new year.
The DfE has been approached for a comment.