Wrong decision for all the wrong reasons. There is no "need" for extra airport capacity in SE England, it is a nice to have, desired by the establishment and by big business to further line their own pockets and supercharge the economy (of the SE) even further, along with the resultant chaos in terms of increased traffic, pollution, further unsustainable population growth and further pressure on housing stock, forcing those already their to move elsewhere.
The world has moved on, and vanity projects such as this serve no purpose, particularly in a country with no reason to pursue endless and unsustainable economic growth.
That's my opinion anyway!