This rumour has been floating about for years, and has been discussed on here before. The rumour was always conditional on Virgin Trains getting the franchise to run the East Coast Main Line.
The rail line has a spur that runs into the airport. The idea was that pax would deplane and get straight onto a train that would which them into the centre of London in not much over an hour.
Earlier this year the franchise was up for grabs again. Virgin made a bid, but GNER kept it, I assume for the forseeable future.
I like it as a rumour though,.... it is only about 15 miles from where I live and I will be looking for a new job in 2 years;) .
It also has the runway capacity to take the A380 - it is about 2 miles long, I believe.
Interesting what it says at the bottom of the thread, putting NEMA forward as a possible expansion airport. [8D][8D]
Nick