One of the better however more aggressive responses is to establish green and red zones as they did in Australia. The movement of people around the country is a prime reason why spread is so effective.
We live on an island so it should be very easy. Close the borders, establish internal borders (aka zones with enforced tiers) and then track and trace within the red zones, surveillance via random testing in the green zones.
We have tiering already but it's completely pointless when the tiers are not separated by physical borders. In November I could travel from Tier 2 to Tier 4 with no rules whatsoever to prevent this and that defeats the object.
Australia reported 5 cases yesterday.