Personally I just cannot see a third runway at Heathrow (some of us remember when 05/23 was active then somebody decided to build a terminal at one end - foward planning I don´t think so) being built. Nimbys and public enquiries etc spring to mind. As for Northolt another non starter I´m afraid just would not work. The only solution to my mind is joint runway operations at Heathrow (take-offs and landings on both runways) but we know that won´t happen because the CAA (Campaign Against Aviation) would not allow it on safety grounds - but it happens in other countries.
Going back to see Barling Magna eulogise over easyJet´s Southend operation may I remind everyone that the three aircraft operating from that airport were transferred from Stansted but good luck to Southend I think they will need it in the long term when the introductory deal from Stobart runs out.