The RAF were severely lacking an air-to-air aircraft, so the focus was on AST.403 resulting in AST.409 being a dead end for new aircraft.  With a significantly reduced budget, BAe returned cap in hand to St Louis to license McDonnell Douglas technology for the UK’s second generation Harrier.  I wonder if all the funds spent on the P1205 to the P1216 would have delivered the P1185? 

The Harrier GR5 was the designation for the RAFs second generation Harrier, and it entered service shortly after the AV-8B.  The Harriers were upgraded through the GR7 specification into the multi-role  GR9 model. The GR9A was developed when the UK decommissioned their Sea Harrier FA2s. The upgrade gave the aircraft the capability to fire AMRAAMs rather than sidewinders and gave it the systems capability to interface with airborne early warning aircraft. The option of swapping in the Sea Harrier's air-to-air radar was investigated, but was discounted on cost.