"Drop Dead Date"
This is the term the government has used for the date at which all properties regardless of when they were marketed will need a HIP. i.e. all properties marketed before the deadlines of 1st Aug (4 bed +), Sept 11th (3 beds) and Dec 14th (1/2 beds). In fact the date is yet to be determined although it would be prudent if you are currently marketing your property for sale without a HIP that you make sure this is not seen as detrimental compared to newly listed and equivalent house which will have the HIP pack available.