From Sunday, every household in Belgium can invite up to four guests to their home. Two sets of four people make a “corona bubble”, who can visit each other’s homes. No one else is allowed into the domestic social circle. The concept, also being discussed by the British government, opens up the biggest social minefield of the coronavirus lockdown.

Belgium’s prime minister, Sophie Wilmès, announced the plan last week, after being accused of prioritising the economy over people’s wishes to be reunited with friends and family. Allowing social bubbles to start on Sunday, Mother’s Day in Belgium and much of continental Europe, is no accident.

“The physical separation from those whom we love has in some cases become unbearable,” Wilmès said, but visitors are told not to hug or exchange the typical three-kiss greeting. The government expects guests to stay 1.5 metres apart and suggests people meet in gardens or on terraces where possible. Authorities say it impossible to police the policy, so they are relying on people’s sense of civic duty.