Heathrow airport, unlovely and unloved, will soon become even more unwieldy if the government has its way. An airport that regularly shows itself to be congested, badly run, claustrophobic and simply in the wrong place, is to be expanded. Its fifth terminal will soon be opened, to be followed by a sixth. At the end of this month the consultation period on plans for a third runway will end. This is a project that ministers appear determined to speed through the planning process. The consequence will be that the number of flights using Heathrow will expand from 480,000 to more than 700,000 a year, inflicting further misery on the 2m people in 12 local authorities who campaigners say suffer a serious loss of quality of life as a result of being under the flightpath.

Even at this stage it is not too late to call a halt. The argument is straightforward. Most countries have built new airports well away from the cities they serve. Heathrow, the world’s busiest international airport, grew out of an old RAF fighter station, not careful planning. Flights in and out pass over the city, inflicting significant noise, pollution and potential danger. If BA flight 38, which crash-landed at Heathrow last month, had come down seconds earlier, the likely loss of life would have been huge.

There is a simple and affordable solution. A new airport could be built on artificial islands in the Thames estuary, away from the overcrowded city but close enough to be served by fast transport links. Boris Johnson, Tory candidate for London mayor, has given his backing to it, describing the expansion of Heathrow as entrenching “a planning error of the 1960s”. There is a proposal on the table, an £11 billion scheme to build an airport on reclaimed land near Cliffe in Kent and Canvey Island in Essex. Money is no reason to reject it; the third Heathrow runway will cost £13 billion. Heathrow can never be a sustainable solution to Britain’s 21st-century needs. A new airport in the Thames estuary just might.