LONDON — Britain has begun cautiously easing lockdown restrictions despite warnings from some health officials that the risk of spreading COVID-19 was still too great.

Some schools are reopening and some social restrictions have been relaxed, allowing people to have limited contact with family and friends as long as it is done outdoors and with social distancing. Restrictions on some of society’s most vulnerable have also been eased as the government moves to restore some normalcy in daily life and to revive the economy.

Business Secretary Alok Sharma told the BBC that the government is taking action in phases to ease restrictions in place since March 23. He says “this is not a dash.’’

The Association of Directors of Public Health has warned that experts are worried that the government is moving too fast.