Transfer of Site from Parent - Taxable under new proposed tax?

I have received planning permission to build a house on a piece of previously argricultural land from my parents and would like to know if this would be taxable under the new proposed tax to be introduced in the December budget.

The land is still in my parents' name so I will be transferring it into my name in the future. If it is taxable under the new tax (if it is introduced) then does anyone know if I have time to transfer it by December?