The Chief Medical Officer 's Annual Report , the 50th report produced since a chief medical officer was first appointed , cites research that a 50 pence per unit minimum price would mean that a bottle of wine could not be sold for less than £ 4.50 , whisky for not less than £ 14 , a six pack of lager not less than £ 6 and a two-litre bottle of cider not less than £ 5.50 .