I think there's absolutely nothing that the government could have done, or could yet do to stop Omicron
Closing indoor mixing (ie lockdown with essential shops capacity limited) will still reduce cases I'm sure, there's no suggestion the reproduction rate is high enough anywhere to change that conclusion.
Of course, like previous lockdowns, that's just postponing - however 3 months for a new vaccine and the time spent building a more efficient distribution network might "Save May Bank Holiday Weekend".
On the concerns earlier over Ventilation Beds - in England they have been essentially static for 3 weeks, fluctuating between a low of 764 and a high of 806, today the number is 779, this is still just a reflection in the Over 60's case rate over the last couple of months, nothing's yet changed there that I can see.