> I think most people seem to be underestimating just how bad this is.

No, there is no reason to panic yet. Concern, perhaps, but not panic.

There are a truckload of confounding factors in the middle, including potential "founder effects" (when a variant becomes dominant because it is the first to take hold, and just outruns the others out of larger starting numbers).

There is not yet solid proof of "70% more transmissible" given that all the data there are is the SAGE meeting minutes. We don't know from where the data came from, and how the estimations were made. There are huge uncertainties.

Until the biological analyses are done, one needs to keep their cool. Sadly, that wasn't what the UK government did.