Young people must be put at the heart of the inquiry into the UK’s handling of the coronavirus pandemic, the Children’s Commissioner has told its chairwoman.

Dame Rachel de Souza said children have expressed to her the long-term impact the pandemic has had on their wellbeing and happiness.

She has written to Baroness Heather Hallett, urging her to put children at the centre of the UK Covid-19 Inquiry’s work and ensure they are prioritised.

It comes in the same week as more than 40 of the UK’s leading children’s charities and child development experts issued a warning to the inquiry chairwoman about “unacceptable delays” in taking evidence from children on lockdown and its effects.

During the pandemic children across the country sacrificed so much to keep us all safe

The letter from the Children’s Commissioner, first reported by the Daily Telegraph, has not been published.

But in a statement accompanying it, Dame Rachel said: “As Children’s Commissioner, it is my job to ensure that children’s voices, views and experiences are heard by policymakers, Government and the Covid inquiry.

“During the pandemic children across the country sacrificed so much to keep us all safe.

“Children and young people have told me how lonely they felt, how much they missed school, seeing their friends and socialising. Now, they continue to tell me about a long-term impact the pandemic has on their wellbeing and happiness.

“That’s why I have I have called on the chair of the Covid inquiry to ensure that it has children and young people’s views and voices at the heart and centre of everything they do.

“I will continue to call for the inquiry to recognise the pandemic’s impact on children and make sure we are prioritising them in recovery.”

Baroness Hallett is “committed to investigating the impacts on children and young people”, an inquiry spokesman said on Tuesday.

Meanwhile, Save the Children UK, the NSPCC and the National Children’s Bureau were among those who signed an open letter in recent days asking Baroness Hallett to commission experts to start recording children’s experiences.

Dan Paskins, director of UK impact at Save the Children, said: “Children are being silenced by this inquiry.”

The organisations complained that the inquiry’s Every Story Matters campaign, which allows people to share stories of their experiences of the pandemic, is only open to those aged 18 and over.

They called on the inquiry to publicly commit to hearing from children, especially those from disadvantaged backgrounds or those who experience other inequalities or discrimination, and use this research to inform the scope of a children’s module.

The inquiry is expected to announce the next 12 months of investigations in early 2024, with future investigations expected to cover education, children and young people.

A spokesman for the inquiry said: “Inquiry chair Baroness Hallett is committed to investigating the impacts on children and young people – including health, wellbeing and social care. It is one of a number of topics which the inquiry must investigate that are set out in our terms of reference.”