Eyeballing this, only 11 of the top 50 richest people in the UK have property as their source of wealth.

There's quite a number of very rich foreigners who economically have very little effect on the UK apart from monopolizing scarce inner city property.

So? Let them be violent. What are they gonna do? They don't have guns like in 'Merica.

They're dangerous not because they'll be violent (they won't be), but because they hold missive political leverage.

Not the structure built on it (well ... not much ... and you can often just tax that through the resources it consumes).

Not only are you taxing the asset that can't flee the country, and which the poor typically don't own, you also incentivise efficient land usage (it becomes too expensive to be a NIMBY).