Schools reopened in England on Monday, the first step in the gradual easing of COVID-19 lockdown measures.
In-person classes have been restricted since January, as Britain grappled with the spread of a coronavirus variant. The recent decline in infections led to the easing of rules.
Students and their families, school bus drivers and others are offered simple test kits for free, to allow coronavirus testing twice a week.
British authorities say they will consider shortening the summer holidays to make up for the delay in studies.
Other restrictions in England are due to be lifted through June.
Stores, hairdressers and outdoor dining could reopen as early as on April 12. Movie theaters and hotels could come next in May.
However, government officials are calling for vigilance. They say the easing of lockdown measures would depend on progress in vaccinations, reducing infections and relieving the demands on hospitals.