What do the new restrictions involve?
In brief: an Italian-style lockdown to force people to stay at home beyond a small range of very limited circumstances. Under the terms explained by Boris Johnson in his TV address, people will be allowed to leave home only for the following reasons:
shopping for necessities, as infrequently as possible;
one form of exercise a day, such as running or cycling, alone or with household members;
for medical or care needs, for example to help a vulnerable person;
travelling to and from work, but only if you cannot work from home.
Meet friends, shopping for anything beyond essentials, and gathering in crowds are now banned.