Shed wrote : The market segments which represent LGW's core business are growing, and demand for them must be met somewhere. LGW is the obvious choice for that job,
With greatest (and geniune) respect Shed - Stansted, Luton, Southend etc can address these particular segments just as well and all have spare capacity either now or coming on line - and at the same time take at least some some of the potential loading off the M25 at the same time (thereby addressing Portmanteau's very legitimate concerns, at least in part).
and just to throw in an anecdote - family over from North Carolina this last weekend and staying in Epsom - delighted that they can fly Charlotte-LHR these days instead of Charlotte-LGW, because "LHR is so much more convenient" - their words not mine.