German Health minister is reported as saying that Hancock told him UK would have herd immunity by the Spring (through vaccination).Sprint didn’t bring a cessation in 2020 though. Do you mean summer?
I don't think that's herd immunity but getting through Phase 1, and vaccinating the group that carries 99% of mortality risk would effectively end this epidemic as a national preoccupation.
It depends on being able to execute the vaccination on that scale and no vaccine evasion.