Cretinous Labour.
The current 2m mansion tax simply drove down asset values by its very implementation, meaning less revenue for the exchequer from 2028 - of course, Labour didn’t model that, I’ll bet. Now, with the 1.5m, they will simple continue to drive down asset values.
All this against a backdrop of tightening monetary policy, which, yep, you guessed it moves inversely to asset values - driving them down further.
It really is a race to the bottom, thanks to the socialists.