Building construction in the UK is not the fastest most-frequent thing to start with. And planning constraints can be quite strict[0].

> Julia Moulder, development director at Catalyst and chair of the G15 development committee, said: ‘If you can’t source the brick and you change it you need to go back through the planning process, and that is something that’s started happening. I think it is going to start to knock on through into delays.’

> Ian Tallentire, development director at Home Group, said he has had three or four recent instances where a brick has been changed, necessitating new planning conditions.

> ‘I have had project managers on the phone saying we need to keep going, and then you just have to make the call. If the bricks are very similar I am sometimes happy to take the risk and then go back and sort the planning permission out,’ he said.

As with most well-meaning legislation on building in Anglophone countries, these schemes are all highly-popular, cause death by a thousand cuts, and then people who like them afterwards go on to complain about how 'corporations' or 'immigrants' or 'Airbnb' or some other bogeyman is responsible for "The Housing Crisis" and so on. Before you know it, you will be lobbying your government to declare a Housing Emergency[1] and asking for them to add more requirements to building housing to ensure that sufficient housing is built; and they will gladly acquiesce to the will of the people which, while strong, can nonetheless not fight physics or economics.

0: https://www.insidehousing.co.uk/news/brick-shortage-delay-th...

1: https://www.parliament.scot/chamber-and-committees/committee...