Rating (Empty Properties) Bill

What is magic about the period of three months? I envisage a situation in which a family have an unoccupied property, perhaps because a business has folded, and the family, who are not particularly wealthy, intend to put the property on the market. They might have to deal with a liquidation or bankruptcy of one of the partners, and there might be a delay in marketing the property. In many cases, a good argument could be made for the exemption to run for six months.