For almost 50 years, the aviation industry and its lobbyists have argued for expansion in the south east of England,
in particular a new runway, citing improvements to the 'consumer experience', capacity bottlenecks and UK-wide economic benefits as justification. Oddly, no evidence has been forthcoming that the lack of an additional runway over those 50 years has had a detrimental effect.
Successive governments have oscillated between pressing ahead with expansion and putting it on the backburner because of social and environmental impacts. However, with the appointment of the Airports Commission (AC) in 2012, a detailed analysis was carried out on the economic benefits and environmental impacts of a new runway.
The terms of reference were notable, deeming the runway a response to a 'requirement for additional capacity to maintain the UK's position as Europe's most important aviation hub', eschewing economic reasoning, instead focusing on how to keep up with the 'competition' from Europe.
The work of the AC was surprisingly thorough, but the conclusion was never in much doubt. With conventional economist Sir Howard Davies in charge and the Commission packed with Department for Transport (DfT) officials, a new runway at Heathrow was duly recommended. After further work on the impacts and a major consultation late last year, the government's view remains unchanged.
The impacts of a new runway itself are appreciable as it would devastate a great wedge of London's precious Green Belt. But the biggest impacts arise from the massive increase in aircraft and passengers proposed: 260,000 flghts and 45 million passengers a year.
Some distance down the public's list of concerns - but probably the most important issue of all - is climate change. Aviation is the fastest increasing contributor of CO2 emissions and the hardest to mitigate. Unlike electricity generation or road transport, there is no technical fix such as electric planes or genuinely sustainable fuel on the horizon.
The government's Committee on Climate Change (CCC) recommended aviation emissions should not rise above 37.5 million tonnes CO2 annually if the UK is to meet its climate target of an 80 per cent cut by 2050. But even this cap would mean that other sectors of the economy would have to cut by 85 per cent instead of 80 per cent, with the AC calling for drastic action to keep within limits.
The government's response was twofold. Late last year, it re-estimated the CO2 emissions and, conveniently, they were within striking distance of the CCC target of 37.5 million. The second response was to claim that aviation emissions don't count towards assessing the UK's contribution to climate change, assuming, wildly, that aviation will be part of a global 'carbon trading system', where every tonne of CO2 produced by aviation is offset by a reduction in some other economic sector.
On noise and air pollution, the AC and DfT have taken to making overly optimistic assumptions when estimating impacts. They claim that noise from a three-runway airport will affect only a fraction more people than two runways, despite a 50 per cent increase in air traffic, while when ClientEarth took the government to court over air pollution, it was found to have no credible plan to bring air pollution within limits, even without an expanded Heathrow.
So why is there such keenness in many quarters for expanding Heathrow? The claim is nearly always economic benefits. But using a 'Net Present Value' calculation, which takes into account all the costs and benefits over a 60-year period, the government's net figure is a range of ?2.2 billion to ?3.3 billion. Compared with the UK's economic output of about ?2 trillion every year, the impact of Heathrow expansion is at worst negative and at best negligible.
So what next? There will be a vote in the House of Commons, probably in the summer. If this is in favour of a third runway, Heathrow will submit planning applications while government support, including taxpayer subsidies for surface access, will be mobilised. But resistance to this monstrous scheme continues to grow and there is still all to play for.