Phase 2 deal with their woeful reproductive capacity. Add genes from a species capable of rapid breeding. You will choose chavs as a readily available local source. The consequences will be well beyond your most optimistic expectations. You will relocate your base to the office areas beneath the reading room at the British Museum (ref Possession -AS Byatt) to wait out the carnage (fear of institutions of culture was an unexpected side effect of the genetic splicing). Alternatively a Mississippi steamer on the Thames (ref http://www.steamboatbordello.com/ )