20k cases and 1631 deaths, 3341 hospital admissions
Some good news about cases coming down at least.
Regarding flights, it's about the new variants in South America and South Africa. If you keep allowing people in carrying certain variants it becomes tricky to control and trace so there's good reason to do it now.
Back in March April Uk had millions of people abroad. In 2019 we made 19 million visits to Spain alone so I don't think quarantining was on the cards. Incidentally the cases swamping the UK were nearly all linked to people coming home from mainland Euopean hotposts in France Italy Spain and ski resorts. Blocking China wouldn't have made a difference for the UK, the virus was already spread from China to mainland Europe's big tourist spots.