I've been thinking about Boris' announcement yesterday and you know I am seriously wondering if the government is fully expecting these relaxations to fail?
Of course i am no expert and may well be wrong, but it seems obvious to me that we are perilously close to an R of 1 and that therefore any increase in activity which involves more people mingling (such as going to work!) will push it over 1. If R was significantly lower than 1, surely you'd see death rates falling dramatically (on average) every day, but they are not. Yes they are falling, but not dramatically. Our death rates have halved over the last 4 weeks, but that is not a precipitous drop. In fact the 7-day moving average deaths rates are falling only by around 21% - 22% per week. That equates to an R of around 0.97! (Of course the maths is a lot more complicated because of delays between infections and death rates etc, but it's a reasonable estimate.)
I am convinced the reason for the relaxations - modest though they are - are driven by political pressure to get the economy moving again to the greatest degree possible, as soon as possible. Not by any confidence that the virus is sufficiently under control that we can ease off.
And I am also convinced they we will start to see a reversal in the previously declining figures and infection and death rates start to pick up again. I think a return to lock down is inevitable, and I am wondering if the government knows this, and that we are simply going through this step so it can say to those pushing for an early return to work "see - we told you it was too early". That would IMO fit with Boris' very cautious language yesterday where he made it very plain that these relaxations were conditional upon the figures remaining stable or declining and any increases will mean we are back in lockdown again.