Cornwall children's reading, writing and maths abilities are worse than before the coronavirus pandemic, new figures show.
It comes as Covid-19 continues to wreak havoc on pupils' development across England, with attainment in key subjects remaining significantly worse than before three successive lockdowns in 2020 and 2021.
The Association of School and College Leaders said schools are working hard to improve results, but they are "hamstrung by the Government's inadequate education recovery programme".
The latest Department for Education figures show 58% of 6,342 eligible pupils in Cornwall met the expected standard in reading, writing and maths in key stage two in the 2022-23 school year.
This was up from 55% the year before, but remained below pre-pandemic levels – in 2018-19, 61% met the expected standard.
Nationally, just 59% of pupils reached the expected standard in reading, writing and maths in 2022-23 – unchanged from 2021-22, but still well below 65% in 2018-19.
Meanwhile, Hackney in London was the only area in the country with comparable data that saw children's ability in key subjects improve during the pandemic.
The Government aims for 90% of key stage two children to meet the expected standard in reading, writing and maths. No area in the country is above 75%.
Tiffinie Harris, primary and data specialist at the ASCL, said the results clearly show schools are still feeling the pandemic's effect on education.
Ms Harris said: "Schools are doing everything they can to improve results but have been hamstrung by the Government’s inadequate education recovery programme following the pandemic.
"Primary schools are also suffering from a lack of funding, as well as teacher shortages that are having an impact across the education sector. It is very difficult to raise standards under these circumstances.
"Unless the Government is prepared to make substantial, ongoing investment in education, their target of 90% of children achieving the expected standard in reading, writing and maths will not be achieved."
The figures also show the gap between disadvantaged children and their classmates shrunk, with the proportion of disadvantaged children reaching the expected attainment across reading, writing and maths rising slightly from 43% to 44%.
Meanwhile, special education needs pupils also saw a rise in their attainment, with 20% reaching the expected standard – up from 18% the year before.
The Department for Education said its "mission is to make sure every child has a world-class start in life".
"It is great to see an increase in the proportion of disadvantaged pupils and those with SEN meeting the expected standard in reading, writing and maths," a spokesperson said.
"We have been relentlessly focused on closing the gap between disadvantaged pupils and their peers, and we continue to fund our flagship National Tutoring Programme to help young people make up for time lost during the pandemic."
"We also continue to drive up standards as demonstrated by England coming fourth out of 43 countries that tested children of the same age in the PIRLS international survey of the reading ability of nine-and-10-year-olds," they added.