As I recall the sequence was, Boris announces plans for a partial lockdown (like Sweden), and then as if a switch was thrown announces a heavy lockdown, and uses figures from the “experts of choice” (ICL) to justify doing so.
“Experts of choice” because they provide the advice the government asks them to provide to justify government policy, whilst hiding behind the “experts”.
I think this explains ICL’s record of poor “expert” advice, such as advice to kill millions of cattle as solution to cattle catching a cold during foot and mouth outbreak. Don’t know, but suspect killing the cattle was part of some EU deal over quotas. But the quota deal was hidden behind the “best expert advice money can buy”!
Its claimed (and I don’t doubt it due to Boris’s liberal instincts) he didn’t want the heavy curfew and wants to lift it asap, so perhaps his illness (or poisoning as CNN announced he was covid free when he left hospital!) was a tactical way to keep out of the way until its safe to emerge to lift the lockdown without, he hopes, taking the blame. This will happen when Trump beats off Impeachment 3 and lifts the lockdown in America.