Who is liable for what 5 Infrastructure-levy regulations may set out— (a) the kinds of development in respect of which infrastructure levy is payable, 15 (b) who is liable to pay infrastructure levy in respect of a development, (c) when liability to pay infrastructure levy in respect of a development arises, and (d) the amount to be paid by way of infrastructure levy in respect of a development (“the payable amount”) either by— (i) stating the amount, or 20 (ii) setting out how it is to be calculated.