WHEN workers on the London Underground go on strike, Britain’s capital becomes an odd cocktail of the miserable and the carnivalesque. Blitz-era double-decker buses are drafted back into service. Queues for taxis wind around buildings. Hospital emergency departments fill with out-of-practice cyclists and rollerbladers. For the wobbly, a strike day is a chance for exercise; for the ostentatious, an opportunity to preen (unicyclists mingling with pedestrians in the hairier quarters of the capital). Some even break the habit of a lifetime and venture a conversation with those into whose armpits they are pressed, daily, in the morning crush.

The disruption is immense—a stoppage on July 9th reportedly sapped London’s economy by £300m ($470m)—and strangely reminiscent of Britain’s past, when industrial action by hard-left unions claimed tens of thousands of working days every year. With another shutdown looming on August 5th, Bagehot is tempted to join his fellow commuters in tutting about outfits like the militant National Union of Rail, Maritime and Transport Workers (RMT), whose Marxist leadership exploits its monopolistic power to extract for its members pay and perks much more generous than those in comparable professions. He is, however, also curiously cheered by the strikes.

Why? London is growing. In February it passed its previous population record of 8.6m. Immigration from other parts of Britain, Europe and the wider world, combined with an above-average birth rate, put it on track for 10m by 2030. It is also centralising: the rise of its high-skill knowledge industries, which tend to form clusters, concentrating employment in central areas like Canary Wharf (finance), Old Street (technology) and Chancery Lane (law and business services). London inhales about 2m commuters every morning, exhaling them back out to dormitory towns and suburbs at the end of the day.

As its diaphragm becomes stronger, the city’s windpipe is becoming blocked. One recent report for the London Assembly found that four in five Underground users experience “discomforting overcrowding”. Stations are busy from ever earlier in the morning until ever later in the evening. In March a woman on a packed platform was dragged under a train. In the same month the throng at London Bridge, a major interchange, was so dense that people had to vault ticket barriers to avoid being crushed.

Money for improvements is limited. Fares are already eye-wateringly high (a monthly pass costs £225.10, compared with the equivalent of £74.63 in New York). The government already spends a disproportionate amount on London’s infrastructure; northern politicians grouse about the cost of Crossrail, a new fast line through central London and out into the suburbs, currently under construction.

Even when improvements go ahead, working on a Victorian network and around the daily surge of passengers is slow and disruptive; like operating on a patient as he goes about his daily business. Progress thus lags behind demand. Sir Peter Hendy, a former boss of Transport for London (TfL), the body responsible for the city’s public transport, predicts that Crossrail will be “immediately full” when it opens in 2018.

What the London Underground reveals about work in the capital That leaves operational refinements. TfL is replacing ticket offices with machines and moving staff onto platforms to speed the flow of people through the stations. Attendants with loudhailers instruct passengers like cinema directors: “stand back”, “use all the doors”, “stand away from the doors; next train in one minute”. And in September TfL plans to introduce 24-hour services on five lines, to accommodate London’s growing nocturnal economy. The unions reply to the change (as they did to the ticket-office closures last year) with strikes, arguing that TfL’s offer of £2,000 in bonus payments, plus an above-inflation pay rise, is inadequate compensation for the inconvenience of night work. They also claim the plans put safety at risk. The strikes are, of course, a failure of sorts. Negotiations between TfL and the unions are beset with accusations of duplicity and provocation. Moreover, if London’s puny mayoralty had the tax-raising powers of its New York equivalent, the city could channel the economic benefits of infrastructure improvements into new investment.

The price of success

Short of such political changes, London leaves little room for compromise between the Underground’s controllers and its drivers. The city’s transport needs are growing too fast for TfL to delay operational changes or phase them in more gradually. The network’s need for investment is too great for it to avert the strikes by giving in to the pay demands of the RMT and its sister union, ASLEF. Prices in the capital are too high for union members to let their representatives curb those demands (though generous, drivers’ pay falls short of the £77,000 per year that KPMG, a consulting firm, deems necessary to buy a starter home in London). The city’s dominance inspires too much resentment from other parts of the country for central government to throw more money at it.

The strikes, then, are the product not only of the unions’ monopolistic power, but more fundamentally of London’s economic success. At a time when it is fashionable to up sticks and move to cheaper, less squashed parts of the country (“Goodbye London”, was a recent, typical broadsheet feature), they are a reminder that, despite everything, millions want to live and work in Britain’s capital. As cities from Blackpool to Brindisi struggle with high unemployment, London booms, its opportunities and wealth sucking people in. The RMT may have its banners, its anti-capitalist slogans—and its strikes. But its tactics work only because, week after week, ever more people contort themselves into a cramped steel cage for the ride to a place where they can get on, up and—perhaps—rich.