Heathrow Airport - different train of thought

My unfavourite airport at London Heathrow (LHR) has risen to fourth in the busiest airports list according to Airline Business magazine.
The airport, to the west of London, handled 30.8 million passengers in the first half of 2000, experiencing 11.5% growth when compared with the same period last year.
That moved LHR up one place to fourth in the rankings on the world list behind first-placed Atlanta Hartsfield International (ATL), Chicago O'Hare (ORD), and Los Angeles International (LAX). London's Gatwick Airport is in 26th place.
All this begs the question when are they going to connect Heathrow with the southern rail network? A four mile spur line to Feltham, on the drawing board for many years, would open up many routes to the south, including a connection to Gatwick.
This would encourage passengers to reach Heathrow by public transport, a stated policy aim, and alleviate pressure on some of the busiest motorways in the world. It would also be a money making opportunity. What are we waiting for?