"...Mr Grailing said putting it [the new Heathrow runway] on a ramp over the M25 would be cheaper than putting the new runway IN A TUNNELL UNDER THE M25....."
My mind is boggling at how wide this runway tunnel would have to be to accomodate jumbo jets... never mind how they would land IN THE TUNNELL if the wind was eastery!!
Listen from 15 minutes and 55 seconds.