It would be interesting to know to what extent that is a viable option with HS2 and Heathrow?
@H F Stephens states in a previous post that Heathrow is not running at capacity, but has capacity issues at certain peak times. Are those peak's impacted by a number of regional flights, which could have been replaced by HS2? (I think I read recently that there are 150 flights a week between Edinburgh and Heathrow for example)
EDIT: This post by HFS on the HEX thread was interesting, but my assumption is that whilst it will optimise Heathrow's capacity, it wouldn't address the peak time runway capacity issue?
"Any properly strategic review (short of closure and relocation, but not East, South or West) would almost certainly prioritise the relocation of the fuel farm, full development and completion of the ’Toast Rack’; abandonment of the third runway proposal, along with closure and demolition of Terminal 4."