Imposing a tax on buildings makes no sense

The mansion tax is a tax on an asset rather than labour so in that respect it is similar to a land tax. However the important difference is that land ownership is equally inconvenient to us whether or not there is a house on it. We are penalising something which has no negative impact on other people.

A land value tax on the other hand makes more sense because we are indifferent to whether there is a house on the land... in either case we have no right of access. Land ownership is a cost to everyone but the property owner. For this reason it makes sense to impose a tax on land not on buildings.