Herd immunity was put on the table by Cummings back in March. Spin it as you like, this is a fact.Well looking at this I just Googled it doesn't seem to be clear cut - according to this that was the advice that was coming their way initially although it was apparently "never policy" and they did change it.
Chris Whitty and Sir Patrick Vallance were alarmed by questions over the controversial concept, emails show.www.bbc.co.uk
It just looks to me like you're trying to establish some kind of blame for a deliberate act rather than having poor strategies under consideration apparently based on advice from people who should know. It's been said many times it was never as simple as health or the economy as the two things are inextricably linked. Most governments it seems are having to walk that line.
As to blame? The buck stops with whoever in running the country. N.Z. is a good example of this. Governments knew back in March, how bad this thing was and yet failed to act or prepare. The U.K. government cherry picked the sage advice, to fit their own agenda and then tried to 'blame' the science. Insisting schools an other education institutions return, has seriously increased the infection rate and we are not allowed to talk about this in the U.K. There is still no affective test and trace system in the U.K., in-spite of all of the 'world beating' talk, from our leaders. The WHO said that masks, were an effective precaution back in March, yet the U.K. government refuted this, until September.