Multi - Storey basements and basements underneath historical buildings and gardens will not be permitted. Only single storey basements will be considered.
This situation will prevent from developers from maximising sqf of the property to achieve the highest return on investment and in the same time to create space so needed by new residents.
In my opinion it's a smoke screen for something bigger than just complaints from residents and worrying about "soak away capability of the garden" as councillors state.
From the construction point of view basement digging operation is mostly confined to footprint of the building with just soil taken away and reinforcing bars and concrete brought in. It's less disturbing that for example work on a completely new building or refurbishment of 4 storey building with restoration of the elevation.
Second discrepancy I see is explanation that basements takes away rainwater discharge capability of the natural gardens. I never saw a property which had ideal soakaway area around the house footprint where the rain water was naturally taken away. Most of the houses have a beautiful patios in concrete/stone finishes which are impenetrable for rainwater. Yes basement sump pumps add a little bit of water to main sewers but it's approx 20 litres on the one storey 500sqf basement - equivalent of THREE times flushed toilet during a 24hour period.
Looking at the London Borough of Kensington and Chelsea press releases they noted only 4 cases of intervening in basement related cases where 3 of 4 cases were connected with traffic management complain connected with basement excavation and one with illegal excavation.
Not a lot during a year if you looking at approx 200-300 building sites mostly focused on basements.
In most cases we cannot build higher even if sky above your property is also yours to take hence maybe it would be better to just better control contractors by proper method statements, adhering to strict traffic management rules and in general better overlook of the projects than just ban something which create a small challenge because it's simply EASIER TO DO.
I requested additional information from Kensington and Chelsea council. As soon as I receive reply I will update this section.