Are there any figures available for LHR's contibution the UK Exchequer currently? Because let's be honest within ten years a new runway at Heathrow would be full, so increase the currently available figures by say a third (just to be conservative) and use that as a ballpark figure for how long R3 will take to payoff. Obviously that won't include airport personnel taxes, increased business activity but that's extremely difficult to quantify and open to manipulation by both sides.