The BBC has gained access inside a school in St Helens, in which more than 60% of pupils receive free school meals.
Children and their parents spoke about the educational struggles they face and the ways coronavirus has made these worse.
The CEO of the Three Saints Academy Trust, Kirsty Tennyson, says the gap in educational inequalities will have grown hugely during lockdown.
She says it will take well over a year – and even longer in some cases – to bring poorer children back to the academic level they should be at.
This comes as new figures show that primary school children from the poorest families in England were doing over an hour less learning each day in lockdown, compared with children from richer families, according to the Institute of Fiscal Studies.
The Department for Education said a £350m tutoring scheme would help disadvantaged pupils, and that during lockdown the government provided more than 200,000 laptops and tablets to vulnerable children and those preparing for exams.
Correspondent: Ed Thomas
Camera: Stephen Fildes
Editing: Nick Woolley
Producer: Claire Kendall