The Advanced Projects Group grew out of HSA's bid for Concorde, then studied the possibilities for what might be flying twenty years down the road. Think their drawings were numbered APD-10xx (AP Drawing), but the projects were normally referred to as P.10xx. This was a completely separated series from the main Hawker numbering system. Project work tailed off from about 1971, after the death of Hugh Francis, and the Group morphed into the HQ Research Dept, overseeing all HSA research work.