In this case it's outer London. And, yes, one of the plots has had planning permission for years, and had the owners re-apply regularly for buildings in the 40

In this case it's outer London. And, yes, one of the plots has had planning permission for years, and had the owners re-apply regularly for buildings in the 40-75 floor range, and the council has fallen over itself to approve it each time. The other involved a lengthy planning process with a plan agreed around 20 years ago for developments that are still not complete. What you're describing makes sense in a market where there's plenty of options. In London land is scarce, and developers hoarding it makes it scarcer, and so both land values and housing prices have skyrocketed.