Heathrow has delivered to Government a £49 billion plan for expansion of the airport that will see it build a third runway and create a new tunnel for the M25. The formal submission follows decades of delay and is certain to trigger a huge legal and planning battle with environmental campaigners concerned about emissions and residents worried their lives will be blighted by noise and years of construction disruption. It immediately ran into opposition from the Mayor of London, Sir Sadiq Khan, who said he was against it “because of the severe impact it will have in terms of noise, air pollution and meeting our climate change targets”. The centrepiece of the privately financed plan is a lull length 3,500 metre runway to the north west of the existing airstrips that will cost £21 billion and be built “within a decade”. However, the proposals also include a new terminal provisionally called T5X costing £12 billion and £15 billion for modernisation of the current airport through expanding Terminal 2 and ultimately closing ageing Terminal 3. Heathrow said the project would allow passenger capacity to rise from the current limit of around 90 million to 150 million with up to 756,000 flights each year instead of the current 480,000. It would also deliver lower fares and more improved reliability and unlock an extra 30 destinations. The ambitious expansion, originally proposed in the 1980s but formally approved by Gordon Brown’s government in 2009, was backed by the Chancellor Rachel Reeves in January as a key plank of Labour’s strategy for kickstarting economic growth. Heathrow has claimed that expansion will add 0.43% to the UK’s GDP with 60% of the benefit felt outside London and the south east. It said it hoped for initial feedback from the Government “by September to stay on track for ministers’ ambitious timeline”. However, the plan still faces formidable obstacles, not least a planning process not likely to be completed by 2029 at the earliest. After a period of consultation a planning application is expected to be submitted in 2028. But many west London residents and MPs remain implacably opposed to the project because of the hundreds of thousands of extra flights over the capital and concerns about noise and emissions and legal challenges are virtually certain. Sir Sadiq said: “I remain unconvinced that you can have a new runway at Heathrow, delivering hundreds of thousands of additional flights every year, without a hugely detrimental impact on our environment. “City Hall will carefully scrutinise the new Heathrow expansion proposals - including the impact these would have on people living in the area and the huge knock-on effects for our transport infrastructure, which would require a comprehensive and costed plan to manage. I’ll be keeping all options on the table in how we respond.” Munira Wilson, the Liberal Democrat MP for Twickenham, said: “The Government claims that Heathrow expansion will deliver growth. Yet the less than 0.5% growth it would add to GDP is miniscule compared to the 4% wiped off the UK’s GDP by Brexit. There are also serious questions around how on earth a debt-laden Heathrow can actually finance the massive costs, and how much will end up coming from taxpayers’ pockets. “This is before we even begin to address the environmental and health impacts. Heathrow is already the single largest polluter in the UK, and the Climate Change Committee itself has said expansion would put the UK’s climate goals at risk. It’s also clear we can’t rely on the silver bullet of Sustainable Aviation Fuels to save the day. “The reality is that both the economic and the environmental case are in tatters. There are too many unanswered questions, and the millions of residents across South West London who would be impacted by expansion deserve to know that these decisions are being made on real evidence basis - and are not simply a fait accompli.” Dr Douglas Parr, Policy Director for Greenpeace UK, said: "In what feels like the twentieth season of London Heathrow's Flying Circus, the government has decided yet again to prioritise more leisure opportunities for a comparatively small group of frequent fliers, whilst the rest of us have to live with the consequences of their disproportionate polluting.” Some airlines, including British Airways and Virgin Atlantic are also sceptical because they fear the construction costs will be loaded on to their take-off and landing fees and have lobbied for a shorter, cheaper runway. However, easyJet has welcomed the plan. The plans also require Heathrow to purchase 752 homes. Heathrow said in its submission it will pay “the unblighted market value of these properties, plus a 25% home loss payment, stamp duty, legal fees and moving expenses. Another potential bone of contention is a proposed M25 tunnel under the runway and widening of the orbital motorway between junctions 14 and 15 at a total cost of M25. Heathrow said the tunnel would be built “offline” and then be “switched on” overnight to minimise disruption. Once the new section is operational, the current M25 would be closed to enable construction of the runway to continue to towards the east Heathrow responded to environmental concerns by “confirming its commitment to reach net zero by 2050”. It said carbon from flights was down by around 10% since 2019. The submission says Heathrow’s noise footprint is down by 41% since 2006. The submission says Heathrow “will only deliver expansion in a way that is consistent with net zero 2050, alongside continuing improvement in local air quality and commitments to predictable noise respite and funding for enhanced noise insulation”. Heathrow CEO Thomas Woldbye said: “It has never been more important or urgent to expand Heathrow. We are effectively operating at capacity to the detriment of trade and connectivity. “With a green light from Government and the correct policy support underpinned by a fit for purpose regulatory model, we are ready to mobilise and start investing this year in our supply chain across the country. We are uniquely placed to do this for the country; it is time to clear the way for take-off.” The Heathrow Business Coalition said it “firmly supports the proposal for a third runway at Heathrow. As representatives of the airport’s exporters, supply chain partners, and retailers, we have witnessed first-hand the advantages of a thriving, globally competitive hub. Expanding capacity at the UK’s busiest airport is essential to keeping British businesses at the forefront of international trade". Transport Secretary Heidi Alexander said: “I am pleased to have received the initial Heathrow expansion proposals - a significant step towards unlocking growth, creating jobs, and delivering vital national infrastructure to drive forward our Plan for Change. “We'll consider the proposals carefully over the summer so that we can begin a review of the Airports National Policy Statement later this year.”