More than a third of a million people moved out of the city last year, suggesting a historic turning point

In the leafy village of Essendon, just outside Potters Bar in Hertfordshire, florist Denise Moore is contemplating the reasons she left London five years ago. “I wasn’t really looking to move,” she said. “But my next-door neighbour moved to this village and I came to visit her and really liked it. It’s a lovely place. It suits my needs.”

Moore is one of a growing number of people who are leaving the capital each year. Figures from the Office for National Statistics released last week showed that 340,500 people moved out in the 12 months before June 2018, the largest number since the ONS began collecting data in 2012. London is now the only region of England where more people are leaving than arriving from other parts of the country – only international arrivals are keeping the population steady.

The exodus is having a noticeable impact on the city: 40% of places are unfilled at St Aloysius primary school in Camden, so officials have earmarked it for closure. Stamford Hill primary will probably merge with its neighbour, Tiverton primary school in south Tottenham, and other schools are likely to follow. A declining birth rate is one reason. Parents are leaving London faster than at any time in recent memory.

Everyone thinks they know why: knife crime, outrageous house prices, pollution that blackens your nostrils … But are these the real reasons for the unprecedented exodus?

“It’s quite tricky to give an honest answer to that question,” said Stephen Clarke of the Resolution Foundation thinktank. “Is it graduates leaving the capital because it’s too expensive to live there? Or is it young families being squeezed out by high house prices? Or is it older people who are sick of London? We don’t really have the data. It could be that these things happen when the economy is doing well, and when it’s doing badly people stay put.”

An easier question to answer is where people are going. The ONS figures show that big cities such as Birmingham, Manchester and Bristol get a fair share, but the largest proportion choose places close by: Dartford, Epsom and Ewell, Hertsmere, Epping Forest, Thurrock, Broxbourne – all on the fringes of London either within the M25 or just outside.

In Thurrock and Dartford, nearly two-thirds of all people arriving last year came from London. To the north, more than half of arrivals to the Hertfordshire districts of Broxbourne and Hertsmere were Londoners. Which raises the question: are people leaving London, or is London simply growing beyond the green belt and the M25, swallowing up villages the way it once swallowed the fields around Islington Green or the valley of Peckham Rye?

Essendon is on the menu for Londoners. The hilltop village, most famous for being the victim of a zeppelin bombing raid that destroyed its church in 1916, is a collection of finely manicured cottages, with trailing lobelia at every turn. Many homes here are owned by the estate of the novelist Barbara Cartland, who lived nearby, while outside the village the roads are dotted with estates owned by footballers and pop stars such as Tulisa Contostavlos, an X Factor judge who lived there until 2014.

It no longer has a shop, but otherwise Essendon retains most of the things a rural community needs: a pub (being refurbished), a church, a hall and a school that demonstrates a thriving future generation – it takes 15 pupils a year and has no shortages that threaten its existence.

Vanessa McCallum, a local estate agent, says the number of London families moving to the area around Brookmans Park and Potters Bar has been growing for the past few years. “There’s a real mix,” she said. “People who can’t afford a house in London, families who want more space, people downsizing. It’s such an easy journey into London, so it’s very popular.”

Essendon even has a family blacksmith, a near-forgotten staple of rural life, but the youngest members of the family at Mill Green Forge are facing the same frustrations as their counterparts in the city.

“There’s no way I could afford to live here,” Lewis Penstone-Smith said. The 24-year-old lives in Welwyn Garden City, but even that would be out of reach. “Everything went crazy a few years ago. The only choices now are Hatfield and Stevenage and even they are going up and up.”

There is a risk for London’s constellation of satellites that they become dormitory villages for commuters, who are too exhausted by their jobs and travelling to take part in village life. Essendon seems to have escaped that fate, according to Michael Weir, a shopkeeper who has lived there for 50 years.

“There’s a lot of families in the village that go back a long way,” he said, reeling off the names of several who live in the former council estate in the glebe roads, former church houses built nearly 100 years ago for farmhands who harvested wheat with sickles and scythes. “I don’t think the village has changed all that much. There are a few more houses now. But people want to come back here.” The pattern of people leaving London in large numbers is something that has happened before, and for a long time was a symptom of its decline. When the population hit 8.6 million in 2015, it merely recovered the size it had in 1939.

This was deliberate, according to Richard Brown, research director of the Centre for London thinktank. “It was largely driven by public policy – the foundation of new towns focused industrial investment outside London – and to a certain extent by the general global move away from living in suburbs,” he said.

The revival began in the 1980s, when the government scrapped office-development permits that effectively prevented businesses from setting up offices in the capital.

Facebook Twitter Pinterest St Mary the Virgin, Essendon, Hertfordshire: villages like Essendon, just outside the M25, are a destination for many leaving the capital. Photograph: Brockswood/Getty Images/iStockphoto

“Things like the ‘big bang’ in the city started to bring a more global population into London, the rebirth of Docklands created big space for offices, you had freedom of movement across the EU, and there was a growing cachet and cultural cool.”

So could London return to the doldrums of the 70s? There are risks, Brown says. “Because London has so self-evidently been the financial capital and business capital of Europe, and in some ways the world, people put up with the inconveniences of life. If it stops having that ease of access to European markets and international markets, then whether people are prepared to put up with things becomes more questionable.”

If Brexit leads to fewer jobs, if there are tougher immigration controls – about a third of London’s workforce was born outside the UK – if houses continue to be unaffordable and if the quality of life worsens, then “they could have a strong mutually reinforcing impact”, Brown said.

He is optimistic, though. He cites new registrations of national insurance numbers, showing how many foreigners come to work in London, which had been gradually decreasing since peaking in 2014, but picked up at the end of last year.

In fact he thinks people leaving the capital could be good news. “If people moving out of London are also choosing to move to Birmingham or Leeds, as well as Crawley or Brighton, I think that’s very positive.”

Because although more people are leaving London, more people are arriving too.

“We want to make it possible for people across the UK to come and spend time in London, work for a few days, a week or a few years, and feel that the capital city is something for them.”