Where are the largest cities in Britain?

Sheffield: Is this Britain's third city? (Hint: No.) Image: Mick Knapton/Wikimedia Commons.

The other day, over on that Twitter, I was invited (no, really, I was) to help settle an argument: how big is Sheffield? 

A property listing, for the old town hall, had suggested it had once been the nerve centre of the UK's third largest metropolis. No one seemed quite convinced by this, for the very good reason that everyone involved could think of three bigger cities without breaking a sweat. 

So, I'm going to go out on a limb here and say that, no, Sheffield is not Britain's third biggest city.

But we like to do things round the book round here – so let's crunch the numbers and establish, once and for all, a definitive ranking.

There’s one slight problem with this ambition: cities are surprisingly hard to define. And if CityMetric had a motto, it'd be whatever the Latin* is for “It depends how you count”.


Municipal boundaries

The reason Sheffield had somehow sneaked its way into third place, despite manifestly not being the country’s third largest city, is because it's often listed as the third largest individual local authority in England, with a population of around 553,000. Only Leeds (751,000) and Birmingham (1.1m) are bigger. Actually, so is Glasgow, with 593,000, but for some reason a single list of local authorities covering the entire UK is surprisingly hard to come by.

And already, you can see another problem with this definition: there isn't a London-wide local authority that's directly comparable to these places. Greater London is more sensibly compared to the other old metropolitan counties (West Midlands, West Yorkshire, etc). But while Greater Manchester is a pretty coherent entity these days, several of the others are still arguing about whether they're one city or several.

Nonetheless, in the name of completism, here are the populations of England's metropolitan counties...

  • Greater London – 8,173,941
  • West Midlands (B'ham) – 2,736,460
  • Greater Manchester – 2,682,528
  • West Yorkshire (Leeds-Bradford) – 2,226,058
  • Merseyside (L'pool) – 1,381,189
  • South Yorkshire (Sheffield) – 1,343,601
  • Tyne & Wear (Newcastle) – 1,104,825

...and of some of the bigger official "cities" they contain:

  • Birmingham – 1,073,045
  • Leeds – 751,485
  • Sheffield – 552,698
  • Bradford – 522,452
  • Manchester – 503,127
  • Liverpool – 466,415
  • Bristol – 428,234
  • Newcastle – 280,177
  • Sunderland – 275,506
  • Wolverhampton – 249,470

(Source: 2011 census data.)

Right. Now that's out the way, we can get onto the stuff that's actually useful. 

The urban area

There are a number of other ways of defining city populations, of which perhaps the most obvious is the “urban area” – that is, the continuously built up zone. This, after all, is the thing that feels like a city when you are actually inside it – or, come to that, when you are flying over it in a plane. 

The most up-to-date stats on this measure come from Demographia, a St. Louis-based consultancy, which every year gathers data on every city with a population of 500,000 or more and ranks it in its World Urban Areas Report.

In this year's edition 13 British cities make that list. Here they are, in chart form:

The dominance of London, though, renders the chart almost unreadable – we really only included it to give you some sense of the numbers we're talking about here – so from here on in we'll just present the figures.

Here's that population data again. The first number is their rank in the hierarchy of British cities; the one in brackets is their rank in the world. 

  • 1 (32) – London – 10,236,000
  • 2 (170) – Manchester – 2,639,000
  • 3 (183) – Birmingham-Wolverhampton – 2,512,000
  • 4 (259) – Leeds-Bradford – 1,893,000
  • 5 (390) – Glasgow – 1,220,000
  • 6 (565) – Southampton-Portsmouth – 883,000
  • 7 (570) – Liverpool – 875,000
  • 8 (619) – Newcastle – 793,000
  • 9 (650) – Nottingham – 755,000
  • 10 (701) – Sheffield – 706,000
  • 11 (776) – Bristol – 646,000
  • 12 (824) – Belfast – 600,000
  • 13 (942) – Leicester – 534,000

So, now you know Leicester residents: you're the 942nd largest city in the world. 

A number of comments about this data. Firstly, on this definition, Britain's historic second city Birmingham has been shoved into third place. Poor Birmingham.

Secondly, the only one of the four UK countries without a city of this size is Wales: Cardiff, with 467,000 residents, just misses ranking. 


Perhaps the most unexpected entry here is in sixth place. No one would think of either Southampton or Portsmouth as a major city: considered as a single entity, though, which in terms of sprawl they are, they're bigger than relative giants such as Liverpool or Newcastle.

Oh, and Sheffield barely makes the top 10, so is definitely not the third largest city in Britain. Just to be clear.

But there are other ways of visualising cities. For example:

Primary urban areas

PUAs are, essentially, collections of local authorities that function a bit like single cities. They were created by the Department for Communities & Local Government a decade or so back, as a statistical tool to help it draw comparisons between very different places. The aim was to come up with a list of areas less arbitrary than existing council boundaries; but which still allowed you to count largely independent but touching cities (Southampton and Portsmouth, say) as independent entities. 

Our old friends at the Centre for Cities still use PUAs in their own research, and have conveniently published a map of how they looked in 2014. Here it is:


 

On these definitions, Leeds and Bradford are counted separately; Sunderland isn't part of Newcastle, and Bolton, Rochdale and Wigan are not included in Manchester. These things obviously have a knock-on effect on the final figures for how big city populations are. 

Those caveats behind us, here's the top 10:

  • 1. London – 9,750,500
  • 2. Birmingham – 2,453,700
  • 3. Manchester – 1,903,100
  • 4. Glasgow – 1,057,600
  • 5. Newcastle – 837,500
  • 6. Sheffield – 818,800
  • 7. Liverpool – 793,100
  • 8. Leeds – 761,500
  • 9. Bristol – 706,600
  • 10. Belfast – 675,600

Manchester is rather shrunken; Birmingham is back in second place. Leeds, deprived of Bradford, has fallen a long way down the league tables. And Southampton and Portsmouth, two cities once again, are nowhere to be seen. 

Let's look at one last definition:

Metropolitan areas

Metropolitan areas are, in the most literal sense, the big ones – not simply a city itself, but its suburbs, commuter towns and rural hinterland. On this definition, London isn't Greater London – it's a large chunk of the Home Counties, too. 

The figures below are from a document published in 2007, and are based on data taken from 2001, so the numbers are pretty out of data (hence the inconsistencies with the other lists above). But it's the best we've got so here, courtesy of the EU's ESPON project, are the top 10.

  • 1. London – 13,709,000
  • 2. Birmingham-Wolverhampton – 3,683,000
  • 3. Manchester – 2,556,000
  • 4. Leeds-Bradford – 2,302,000
  • 5. Liverpool-Birkenhead – 2,241,000
  • 6. Newcastle-Sunderland – 1,599,000
  • 7. Sheffield – 1,569,000
  • 8. Southampton-Portsmouth – 1,547,000
  • 9. Nottingham-Derby – 1,543,000
  • 10. Glasgow – 1,395,000

Considered as a metro, rather than a city, Birmingham is way ahead of Manchester – a result of its better transport links to surrounding towns, perhaps. The twin cities of South Hampshire are back in the rankings, and several other cities look a lot bigger when the whole of their economic footprint is taken into account.

Glasgow, however, doesn't: it barely makes the top 10. Compared to cities like Birmingham or Leeds, it doesn't have much of a hinterland.


Towards a conclusion

What should be clear by now is that no definitive ranking is possible. You can say that London is definitely the UK's biggest city, and no one will challenge you. You can say that Manchester is bigger than Newcastle, and be on pretty safe ground. But is Manchester bigger than Birmingham? What's the UK's 7th biggest city? These are questions with no answers.

What we can do, though, is come up with a sort of typology: not a numbered ranking, exactly, but a sort of way of visualising which league cities are playing in. 

Here you go:

  • Megacity: London
  • Second cities: Birmingham, Manchester
  • Major cities: Glasgow, Leeds, Liverpool, Newcastle, Sheffield
  • Large cities: Belfast, Bristol, Nottingham, Southampton/Portsmouth, Leicester, etc.

The latter category is incomplete: other cities, like Cardiff, Edinburgh, Middlesbrough, even Brighton or Bournemouth, probably have a claim to be in there, too. Britain only has one city whose population even gets close to 10m, but a couple of handfuls of them are bobbing around the 500,000 mark.

But the point, in the end, is clear. No way in hell is Sheffield Britain's third city. 

By the way, if you're the sort of person who'd like to read more of this kind of nonsense, you should totally like us on Facebook.

*Dependet quam numeras.

 
 
 
 

Google knows you took the bus: on the creepy accuracy of Google Maps Timeline

You are here. And here. And here. And... Image: Google Maps.

Knowledge is power, they used to say. Nowadays, they say “data is power”, and they’re not wrong. Unlike many of the modern, high-value tradable goods in our society like oil or gold, data is a limitless resource that we’re constantly creating more of day after day.

What the actors who own this data choose to do with it can often be a point of vast contention: should I be happy for Google to reliably know where I am, where I’ve been, and most frighteningly, where I’m going? It’s not up for dispute that the scope of these tools can be immense – but how much of that scope should we take for granted?

Google Maps is a tool full of wonderful surprises. It can plan a journey for you, tell you what deals to get at the supermarket, and give you updates at the bus stop. Some of the things Maps can do, it does without us even asking; Google knows when we pop to the shops, or when we stand by a bus stop.

This concept is called “geofencing”: cross-referencing geolocation data with the services at that location, and issuing notifications to a device on that basis. Google knows I’m in the supermarket because my location matches up with the area the supermarket is known to occupy, and through a complex series of phone masts and wifi access points, it knows I’m between the vegetable aisles. Okay, maybe things aren’t quite that specific, but the detail is stellar – and often, slightly concerning.

A simple flick through the timeline feature of Google Maps reveals that Google can plot day by day where you were, when you went home, and, maddeningly, how you took that journey – or at least, it can make an educated guess. By applying geofencing programming, Google can calculate when we are near a bus stop, and cross-reference that data with bus routes and other bus stops to determine with a reasonable degree of certainty when its users are taking the bus. Google doesn’t go as far as to try and guess which bus, but it could make an educated guess.

The same is true of train stations; pause in one, follow the expected route of the railway line, and travel through additional train stations, and Google will have no trouble in informing you after the fact that you have travelled by train. A reminder that you don’t need to have planned a journey on Maps for Google to surmise this: it is all calculated based on shifting geolocation data, and nothing more.

Walking, cycling and driving are harder for Google to calculate, because there are no geofenced points of entry for these modes of transport. It is therefore likely that, once bus, train and metro have been eliminated from the mix, Google simply inspects the time taken between harvested geolocation data to calculate the transport mode used. But without geofencing, it’s harder to determine the exact route taken by a user: because they’re not following a prescribed route, and because geolocation data is much easier to take while stationary, routes on timeline taken independent of public transport can end up looking… messy.

Google fails to surmise that some of this journey was taken by train and presumes I took an unorthodox drive through Kent in the early hours. Image: Google Maps/CityMetric.

The system isn’t perfect. For one, it can’t account for anomalies. I took a rail replacement bus service recently, and Timeline was dumbstruck by how I’d managed to get home. But the ever-increasing availability of data surrounding transport timetables means that the assumptions Google can make about our transport choices are only bound to get more accurate. That’s important, because its information that few organisations beyond Google are likely to have real access to.

If we take London as an example, we know that Transport for London (TfL) can use data on traffic flows, ticket barriers, and incomes for bus routes to determine how people use a service. In fact, TfL has even used its own wifi services to calculate route maps on the Tube. However, without undergoing intricate surveys, they will struggle to plot exactly how journeys are taken beyond the Tube Map, especially with regards to buses, disparately owned NR services, and so on.


Google has exactly the information to remedy this – and it’s integrated into Timeline, simply because people consented to having their location data collected. If your local borough council asked to do the same, and the only provision it could grant was that you might get a better bus service, many people would probably opt-out. Part of the reason why we accommodate the location-harvesting of Google is because we consider Maps such a vital service, and its domain – at least in terms of its rights to record our geolocation – is hardly contested. Even those of us who use Citimapper regularly tend to have Maps downloaded on our phone.

Google Maps is in a unique position to mark the differences between journeys that are entirely spontaneous and journeys that are pre-planned, because it is measuring both. That information could be highly useful in designing timetables and shaping user-friendly services.

Moreover, as geolocation data grows more precise, it will be able to help us pin down the flows of pedestrians and cyclists in our cities. While it’s possible to gather this data in the public domain without geolocation, it’s economically prohibitive to do so in less densely populated areas. This data would help prioritise cycle-friendly and pedestrian friendly developments on the understanding of where demand is greatest.

This sort of data inevitably carries such a high risk factor, however – not only as far as personal privacy is concerned, but also surrounding efficacy. We presume that if we know every individual's travel patterns, we can design perfect travel services – but patterns change all the time. An algorithm can never incorporate the latest change before it is registered by the system. While data like that collected by Google Timeline could be put to better use by transport authorities, it shouldn't be abused, nor serve as a panacea for good design.

Worst of all, it’s hardly clear that this data is up for public consumption. The furore over data protection means it would be considered deeply unethical for Google to hand this location data over to anyone, let alone a local government body like TfL. It may be moot point; Google itself claims that Timeline is for our own amusement and little more.

But maybe we’d get better services if it wasn’t; after all, geolocation isn’t slowing down anytime soon.