The mutant atrain B1.1.17 is apparently 70% more infectious than the original Sars-CoV-2. That's really a huge problem because the way that negates the various control efforts.
The basic R value for the original virus is estimated to be close to 3, but the various masks, distancing, hygiene and isolation efforts reduce that to around 1.2. Even less in Australia with high compliance and the warm weather. The new strain shows, even with all those measures, an R value much higher. I still haven’t seen a number, but one scientist estimated it is R=5, perhaps R=3 AFTER countermeasures.
That means that a vaccine is going to be the only hope in slowing the spread, but more importantly, it means that more people will have to be vaccinated (or recovered) to achieve herd immunity.
The formula for that is 1-1/R, so if the raw R for the mutant is 5, then 80% of the population will have to have some kind of immunity to stop the continued spread.. An 80% vaccination rate is going to take a vigorous education campaign and probably some carrot/stick inducements.