What is a city, anyway?

This, believe it or not, is London. Image by Tom Tired of London

Okay, there's a question we're going to be wrestling with a lot at CityMetric. I'm not saying we're going to answer it any time soon, but the least we can do is ask it, and explain why it constitutes a problem. Here it is:

What, actually, is a city?

At first glance this probably looks like a stupid question, the sort of thing you'd get from a four year old, like "What are unicorns made of?" or “Why is the sky blue?” But (spoilers) it's not.

To explain why, it helps to have a worked example or two. London, official figures tell us, has a population of somewhere around the 8.3 million mark. Paris has a population of roughly 2.3 million. So, one might naturally conclude, London is a lot bigger than Paris.

Except, if you look at a different set of figures, it's very clearly not.  Demographia has been publishing a statistical guide to the World's Urban Areas for a decade or so now. Its latest edition, published in May, has Paris on 11 million – four times larger than the official statistics and well ahead of London's 10.1 million.

Then you look at this dataset from the official statistical agency of the European Union and the figures get even bigger but the order's swapped again. Eurostat has Paris on 11.9 million and London on 13.6 million.

You don't have to be a geographer to guess that these three sets of figures are working from different definitions. You can probably even make an educated stab at what each set of figures represents. They are, respectively, the population of the region governed by the city's own authorities, of the continuous built up area, and of the larger metropolitan region.


But which of these is ‘right’? The answer is, infuriatingly, all of them – or, if you prefer, none of them.

To most people, most of the time, none of this is actually a problem: no one ever failed to understand the concept of London because they were unclear on whether you were counting Watford or not. But there are two contexts in which it matters a great deal.

One is its impact on the workings of city governments. If you're the official charged with coming up with a strategy for meeting an area's housing or transport needs, say, then it would help to have some control over the whole of that city.

Very often, though, you don't, so infrastructure investment is likely to focus on the city proper: not only is official power strongest there, but its population get a vote in local elections. Administrative borders can thus end up warping the fabric of the city itself. Just look at the apparently arbitrary places where the New York Subway terminates.

The other reason why which this definitional confetti matters is that it poses a massive barrier to anyone who actually hopes to analyse the urban landscape. Professor Geoffrey West is a theoretical physicist at the Santa Fe Institute, who in recent years has conducted a number of comparative studies on cities. “You'd think by now all the urban planners would have an operational definition of a city that you just could look up,” he says, with some exasperation. “Well that doesn't exist."

As a result, the moment you start trying to quantify any aspect of city life – or worse, compare two cities – you run into difficulties. How many people live in Mumbai? What's the size of New York's economy? Which is more densely populated, London or Paris? All too often, the answer is ‘it depends’. "It's a problem that's plagued a lot of our research," West adds. "And it reflects how little work has been done to quantitatively, analytically, and scientifically understand cities."

The upshot of all this is that what a city is, and where it ends, is a surprisingly subjective matter, and any attempt to nail it down is likely to throw up anomalies. All you can do is keep track of which definition you're working from, and make sure you never, ever, compare apples with larger urban zones.

Here, for future reference, is a quick guide to the main ways of defining cities, which we’ll be trying very hard not to mix up.

 

The municipality

The political definition of a city. Paris is 20 arrondissements, New York is five boroughs, London is 32-plus- that-awkward-finance-y-bit-in-the-middle.

The advantage of this definition is that it’s nice and straightforward and easy to exert political power over (or find data on, come to that). The disadvantage is that it tends to throw up anomalies: some municipalities exclude large swathes of suburbia; others include sudden patches of countryside. The official definition of London includes North Ockendon, a tiny Essex village outside the M25, but excludes Buckhurst Hill, a contiguous central line suburb well inside it.

 

The urban area

This, one might think, is the contiguous urban sprawl: the thing you can point to on a satellite photograph, or from a plane by night.

Life, though, is rarely so simple. For one thing, areas of development separated by less than 200m of open space will generally be bracketed together as a single urban area, on the grounds that anything you can cross in under two minutes doesn’t count as ‘the country’.

For another, there are features like parkland and forests to contend with, so sometimes you’ll notice a distinction between ‘urban area’ (which includes suburban open spaces) and ‘built up’ area (which doesn’t).

There is also no single universal definition of what counts as an ‘urban area’. Most countries define it as one with at least 400 inhabitants per square kilometre. In the US it’s 1,000 people per square mile, which is nearly identical; in Australia, it’s 200 people per square kilometre, which isn’t.

 

The metropolitan area

A city's effective economic footprint, typically measured by commuting patterns. Satellite towns and ex-urbs may not look like part of a city – but since they wouldn’t exist without it, the thinking goes, they should count.

There are two problems with this idea, however. The smaller one is that you end up counting a lot of people who reject the idea they live in a city at all, if only because they made a conscious decision not to (hello, Surrey).

The bigger problem is that it's largely subjective. What proportion of people need to commute into a city to be part of its travel-to-work area is a matter of judgement. And what if a town between two cities contains large numbers of people who commute to both? Is Warrington a satellite of Manchester, or one of Liverpool? Does Princeton belong to New York or Philly?

The consequence of all this is that different countries use different definitions. While agencies like Eurostat have attempted to harmonise these, there's no current data set that does so worldwide.

Here’s an example of all these various definitions at work. This is Paris, c2008:

That tiny maroon nucleus is the city proper. Surrounding it you have the larger built up area (red), the official urban area (orange) and the metropolitan area (yellow). Suddenly, you can understand why the figures for the city’s population seem to vary by a factor of four. 

 

Just to make things more complicated...

While a metropolitan area will typically contain more than one urban area, the same can be true in reverse. Look down from an aeroplane, and you might think that San Diego and Tijuana are a single city. But there’s a whopping great international border between the two, which most of the area’s population aren’t free to cross. So is it one city, or several? How do you define them? As ever, the answer, awkwardly, is “it depends”.

 

Lastly, some definitions we won’t be using

The bizarre official phenomenon of British city status, an honorific handed out by the queen, which means that Ely (pop: 20,000) and St David’s (pop: 2,000) have the same official status as Manchester. The equally bizarre habit in some parts of the US, of appending the word ‘city’ to any cluster of four broken down sheds and a dog. What of these, eh?

Well, these are silly and we intend to ignore them. So there.

Images: Photo of Pratt's Bottom courtesy of Tom Tired of London, taken from Flickr under a creative commons license; map of Paris adapted from Wikimedia Commons.


 

 
 
 
 

“A story of incompetence, arrogance, privilege and power”: A brief history of the Garden Bridge

Ewwww. Image: Heatherwick.

Labour assembly member Tom Copley on a an ignominious history.

The publication last week of the final bill for Boris Johnson’s failed Garden Bridge has once again pushed this fiasco into the headlines.

As well as an eye-watering £43m bill for taxpayers for this Johnsonian indulgence, what has been revealed this week is astonishing profligacy by the arms-length vehicle established to deliver it: the Garden Bridge Trust. The line by line account of their spending reveals £161,000 spent on their website and £400,000 on a gala fundraising event, amongst many other eyebrow raising numbers. 

Bear in mind that back in 2012, Johnson promised that the bridge would be entirely privately funded. The bridge’s most ardent advocate, Joanna Lumley, called it a “tiara for the Thames” and “a gift for London”. Today, the project would seem the very opposite of a “gift”.

The London Assembly has been scrutinising this project since its inception, and I now chair a working group tasked with continuing our investigation. We are indebted to the work of local campaigners around Waterloo as well as Will Hurst of the Architects Journal, who has brought many of the scandals surrounding the project into the open, and who was the subject of an extraordinary public attack by Johnson for doing so.

Yet every revelation about this cursed project has thrown up more questions than it has answers, and it’s worth reminding ourselves just how shady and rotten the story of this project has been.

There was Johnson’s £10,000 taxpayer funded trip to San Francisco to drum up sponsorship for the Thomas Heatherwick garden bridge design, despite the fact that TfL had not at that point even tendered for a designer for the project.

The design contest itself was a sham, with one of the two other architects TfL begged to enter in an attempt to create the illusion of due process later saying they felt “used”. Heatherwick Studios was awarded the contract and made a total of £2.7m from taxpayers from the failed project.


Soon after the bridge’s engineering contract had been awarded to Arup, it was announced that TfL’s then managing director of planning, Richard de Cani, was departing TfL for a new job – at Arup. He continued to make key decisions relating to the project while working his notice period, a flagrant conflict of interest that wouldn’t have been allowed in the civil service. Arup received more than £13m of taxpayer cash from the failed project.

The tendering process attracted such concern that the then Transport Commissioner, Peter Hendy, ordered an internal audit of it. The resulting report was a whitewash, and a far more critical earlier draft was leaked to the London Assembly.

As concerns about the project grew, so did the interventions by the bridge’s powerful advocates to keep it on track. Boris Johnson signed a mayoral direction which watered down the conditions the Garden Bridge Trust had to meet in order to gain access to further public money, exposing taxpayers to further risk. When he was hauled in front of the London Assembly to explain this decision, after blustering for while he finally told me that he couldn’t remember.

David Cameron overruled the advice of senior civil servants in order to extend the project’s government credit line. And George Osborne was at one point even more keen on the Garden Bridge than Johnson himself. The then chancellor was criticised by the National Audit Office for bypassing usual channels in order to commit funding to it. Strangely, none of the project’s travails have made it onto the pages of the London Evening Standard, a paper he now edits. Nor did they under his predecessor Sarah Sands, now editor of the Today Programme, another firm advocate for the Garden Bridge.

By 2016 the project appeared to be in real trouble. Yet the Garden Bridge Trust ploughed ahead in the face of mounting risks. In February 2016, despite having not secured the land on the south bank to actually build the bridge on, nor satisfied all their planning consents, the Trust signed an engineering contract. That decision alone has cost the taxpayer £21m.

Minutes of the Trust’s board meetings that I secured from TfL (after much wailing and gnashing of teeth from the Trust itself) reveal that weeks beforehand Thomas Heatherwick had urged the trustees to sign the contract in order to demonstrate “momentum”.

Meanwhile TfL, which was represented at board meetings by Richard de Cani and so should’ve been well aware of the mounting risks to the project, astonishingly failed to act in interests of taxpayers by shutting the project down.

Indeed, TfL allowed further public money to be released for the project despite the Trust not having satisfied at least two of the six conditions that had been set by TfL in order to protect the public purse. The decision to approve funding was personally approved by Transport Commissioner Mike Brown, who has never provided an adequate explanation for his decision.

The story of the Garden Bridge project is one of incompetence, arrogance and recklessness, but also of privilege and power. This was “the great and the good” trying to rig the system to force upon London a plaything for themselves wrapped up as a gift.

The London Assembly is determined to hold those responsible to account, and we will particularly focus on TfL’s role in this mess. However, this is not just a London issue, but a national scandal. There is a growing case for a Parliamentary inquiry into the project, and I would urge the Public Accounts Committee to launch an investigation. 

The Garden Bridge may seem like small beer compared to Brexit. But there is a common thread: Boris Johnson. It should appal and outrage us that this man is still being talked about as a potential future Prime Minister. His most expensive vanity project, now dead in the water, perhaps serves as an unwelcome prophecy for what may be to come should he ever enter Number 10.

Tom Copley is a Labour member of the London Assembly.