Heathrow Airport is prioritising airlines and passengers over local residents in its expansion plans, the London Assembly has said.

More flights and a third runway would be bad for Londoners, according to a submission from the Assembly’s environment committee to the Heathrow consultation.

The west London airport is currently consulting the public on plans to expand from 475,000 flights a year to as many as 740,000 by 2040.

To allow this growth, Heathrow would build a third runway to the north west of the airport on Harmondsworth Moor – including the village of Longford, and parts of Harmondsworth and Sipson.

London Assembly environment committee chairman Caroline Russell said the expansion would not benefit local people.

She said: “The impact of noise and air pollution, increased congestion and the demolition of villages in west London are all reasons the third runway plans should be dropped.

“The UK has committed to net zero carbon emissions and the expansion undermines this commitment.”

She added: “Expanding Heathrow is bad for Londoners, bad for London, and bad for the health of our planet, and that’s why we are recommending that it does not go ahead.”

In a letter to the consultation, Ms Russell highlighted concerns about noise pollution from the airport.

At least 320,000 more people would be impacted by noise above 54 decibels under the plans, according to Westminster’s transport select committee.

This is the level used by the Airports Commission to assess plane noise – but the World Health Organisation says even lower levels can be harmful to humans, arguing anything over 45 decibels can damage health.

Paul Beckford, spokesperson for No Third Runway Coalition, said communities were “last on the list” of priorities in Heathrow’s expansion plans.

Mr Beckford said some communities would experience more noise, while others would be newly affected – but emphasised the “absence of detail” on where these impacts would be, despite hunreds of pages of consultation material produced by Heathrow.

He said: “It’s not simply a new runway – it’s equivalent to bolting a new airport onto Heathrow.

“We’re talking about 30 years of expansion, not just a five-year runway project. That this blight on communities could be going on as long as three decades is quite astounding.”

Expanding the airport would also increase carbon emissions by as much as nine million tonnes a year, according to Heathrow’s own analysis.

The airport is the UK’s single biggest polluter, with 96 per cent of its emissions from flights – but flights are not factored into Heathrow’s analysis of its carbon impact, or its net-zero emissions target, the London Assembly has emphasised.

The third runway was approved by a large majority in Parliament last year, but has been widely opposed – including by new Prime Minister Boris Johnson, who is MP for Uxbridge and South Ruislip.

Mr Johnson, who during his time as Mayor favoured a sixth London airport on the Thames Estuary known as ‘Boris Island’, once said he would “lie down in front of those bulldozers” to prevent a third runway at Heathrow.

Transport Secretary Grant Shapps last week drew speculation on the Government’s commitment to the third runway when he questioned whether the plan “stacks up”.

But a spokesperson for Heathrow said any expansion at the airport would be regulated by legally binding requirements for noise, air quality and emissions.

He said: “We will continue to refine our plans based on feedback, and remain focussed on delivering this critical project which is supported by a vast majority of MPs, trade unions and businesses across the UK.”