LONDON (BLOOMBERG) - Boris Johnson must put vulnerable children at the heart of his post-Covid plans to ensure no one is left behind after the pandemic, England's children's commissioner will warn.

In her final speech in the post on Wednesday (Feb 17), Anne Longfield will accuse the Treasury of an "institutional bias against children," saying it's failing to take account of the "cumulative impact" of multiple spending decisions on families.

She will also talk of her frustration with Whitehall officials - many of whom, she claimed, view children as "remote concepts or data points on an annual return."

She will say: "This is how children fall through the gaps - because too often the people in charge of the systems they need simply don't see them and try to understand their world."

Schools have been closed in England since early January in the third national lockdown, meaning many children have only had one full term of lessons in the last year.

Longfield will call for a "year of opportunity" to be launched once the virus is suppressed, with schools, sports halls and swimming pools opened at evenings and weekends to help children "catch up with confidence."

She will also urge Johnson to extend the 20-pound (S$36) weekly uplift in Universal Credit benefits payments when it comes to an end in April, warning that failing to do so would push 800,000 children into "devastating poverty." Johnson's "promise to 'level up' is just a slogan unless it focuses on children," she will add.

A government spokesperson said: "Protecting vulnerable children has been at the heart of our response to the pandemic, driven by our commitment to level up opportunities and outcomes."