Professor Edgar Morgenroth:

I have laboured with this every once in a while in my day job. It is difficult to come up with a really hard definition that really captures what we are trying to achieve. The example the Deputy gave is a very good one. If all the development is on the edge, is that really compact growth? Probably not. If we compare the highest-density areas with the least-density areas, there are substantial differences in emissions, both from residential sources and from transport. The aim should be to get more of the highest-density development, which then has its own implications in terms of brownfield development, etc. We know that is difficult but it is what we need to do to achieve greater reductions in emissions.