Children should avoid team sports and ride their bikes two metres apart to maintain social distancing during the Covid-19 pandemic.
Deputy chief medical officer Dr Jenny Harries said the Government was not saying to avoid going outside – but to do so in a way which “reduces social contact”.
The announcements that pubs, cafes and restaurants were to close came as schools across the UK shut their gates until further notice on Friday.
During a Downing Street briefing, Dr Harries said it was important to strike a balance between maintaining physical and mental wellbeing during the pandemic.
When asked about children going outside, she said: “For example keeping two metres apart, off for a bike ride together or something, that is absolutely fine.
“And in many ways, we would encourage that.”
But she recommended that children should keep hold of their own bikes, wash their hands regularly and continue to catch coughs and sneezes in a tissue.
Dr Harries also advised against children participating in group activities, telling reporters: “The weather is getting better, we want children to be exercising, but to do so not in groups. ”
The deputy chief medical officer said team games are not encouraged during the outbreak, as she warned against the “social element” of group activities.
“If everybody piles up in shared cars that’s not a good thing to do,” she told the briefing.
“And if everyone tried, they won’t be able to now, but if everybody tried to go to a cafe or restaurant afterwards that would also not be a good thing to do.
“Exercising fine, but cut right down on the social connections.”