I propose to tax property on a "standardised square footage" basis. A certain square footage per person is defined, which is not taxed or is minimal (say, a little less than the current NIC). Further square footage is taxed in a very progressive way, and it does not matter whether it is a different property or the same property. If the property is used for living purposes, it is therefore taxed significantly less than if it is unoccupied, irrespective of whether the owner's family or tenants live there. Therefore, empty and irrationally used properties would be taxed significantly more than rationally used properties. If there are tenants in the property, the tax is small, but in this case, of course, the owner pays tax on the rent. That way, there would be fewer irrationally used properties and fewer black rentals, which I think are now in the majority. The tax yield would thus be higher.