"SHE'S 86," SAYS Jim Carter, service-control manager of Edgware Road Tube station, fondly patting the elegant wood-and-metal panel in his signal box. Installed in 1926, it has 38 levers - red ones for signals, black ones for points "and the yellow to get you out of trouble" - that control the movement of 950 trains a day in and out of the station. A hundred years ago London had the best infrastructure in the world. Its legacy is historically impressive but sometimes difficult to manage. Single-track Tube tunnels mean that breakdowns bring a line to a halt; curved tunnels and platforms, shaped by the Victorians" inability to dig through the hardest rock, slow the system down. For half a century after the second world war the city's rail system mouldered. Making it work better was one of the main reasons why the Labour government created the post of mayor. It remains a serious bottleneck, so hosting the Olympics in the centre of the city was what Sir Humphrey, civil servant to the incompetent politician in the television comedy "Yes, Minister," would have called a "brave" decision. Still, having a mayor has improved London Underground, partly because both incumbents have managed to extract lots of money from government for it. Antiques like the Edgware Road signal box are being replaced by computerised control rooms. The Victoria, Jubilee and Central Lines have been upgraded already; the Northern is being done now. On upgraded lines trains are automatic, which means that they can run more often. On the Jubilee Line, for instance, numbers have gone up from 24 trains to 30 an hour at peak times and from 18 to 24 off-peak. Since control over London Overground was handed to the mayor, that neglected stepchild of the national rail system has been provided with new carriages suitable for commuters - built for standing, with automatic doors - and spruced-up stations. It loops round eastern and southern London, parts of the city that have never before had decent public transport. Mr Johnson is now lobbying to get control of the suburban rail services, too. Mr Livingstone also got the go-ahead at last for Crossrail, which had been under discussion for four decades. The Tube upgrade should increase the system's capacity by 30% and Crossrail by a further 10% - which should both keep up with the population increase and ensure that travelling in London is not as painful as it used to be. But it won't necessarily happen. Although Crossrail survived the budget cuts, the financing of the District, Circle and Hammersmith Line upgrades is not assured, and the Bakerloo and Piccadilly Line upgrades have been postponed indefinitely. Since those lines are nearly 50 years old, commuters who rely on them will suffer. Jam-packed Vehicles enter the Blackwall Tunnel, the main river crossing in east London, at a rate of around one a second in each direction. When somebody breaks down in the tunnel, which happens over 200 times a year, a 600-vehicle queue builds up within ten minutes. If the jam occurs at 7am, it takes around three hours to clear. One breakdown in three is caused by running out of fuel. When Mr Livingstone was mayor he introduced a congestion charge on vehicles coming into central London, which initially cut such traffic by 20% and improved traffic flows. Since then, some streets have been given over to pedestrians, pavements have been widened and traffic-light phasing has been changed in favour of people on foot. All this has made the city a nicer place to wander round in but, along with higher traffic volumes, has increased congestion once more. There are various ways of freeing up roads. Investment in public transport - of which there has been a great deal - is one. Cycles are another, though they are costly too. Londoners can pick up one of 8,300 "Boris bikes" from a rack of their choice and drop it back at another. It is cheap for users - the first half hour is free and the next hour costs £4 to encourage commuter use, after which charges rise sharply - but expensive for taxpayers. They have shelled out slightly more than half of the total cost of £120m, with Barclays Bank, the sponsor, covering the rest. The average cost per bike is £14,460. Technology can also ease congestion. Some 40% of London's traffic lights can sense the length of the queues at each light of an intersection and adjust their timing accordingly. That technology, which is being progressively rolled out, allows 12% more vehicles to make use of the existing road network. From this month, Transport for London is starting to charge utilities £2,500 a day for digging up the busiest roads. That should cut down on roadworks, and therefore on jams. But as the population grows, congestion is bound to get worse again. One way of alleviating it is to bury roads. London already has a few underpasses. There could be more, on heavily used roads and interchanges such as Marylebone Road and Vauxhall Cross, but it is too expensive to be widely used. In America the Big Dig, to bury five miles of highway under Boston, which started in 1987, was expected to cost $2.6 billion. By the time it eventually opened 20 years later, it had cost $15 billion, which made it the country's most expensive road project ever. Another solution is more congestion charging. When he came to power, Mr Johnson abolished the western extension of the congestion-charging zone, reverting to the original area covering just the City and the West End. That was a mistake. If Londoners are not to spend even more of their lives fuming in traffic jams, congestion charging will have to spread. Fear of flying But the politics of roads are nothing to the politics of airports. The argument over how to improve London's air links has been running for half a century. Various plans to expand capacity have been approved by (Labour) governments, only to be cancelled by their (Tory) successors. As a result, no new runway has been built in the south-east since the second world war. The problem is not simply one of airport capacity. Stansted, to the north-east of the city, is half-empty. The problem is hub capacity. Airlines want to fly into places that other airlines use so they can pick up more passengers. That means having a single hub. A measure of the value that airlines place on flying into the hub is the price of landing slots. "Zero against £25m [the price of a landing slot at Heathrow] says that connectivity at Gatwick is not as good as connectivity at Heathrow," says Colin Matthews, BAA's chief executive. Sceptics point out that New York does not have a dominant hub. But New York is hardly a model for London to follow. The only airport experience worse than arriving at Heathrow is arriving at JFK. And New York is not as dependent on foreign business as London is. Companies that operate internationally need direct flights to destinations all over the world. The richer that emerging countries get, the more important this will become. Good connections to capitals are not enough: the economic action is increasingly in second-tier cities. Heathrow has some flights to new emerging-market destinations - Hyderabad, Bangalore and Guangzhou, for instance - but it is, essentially, full. To make room for new destinations, it has to bump off old ones. Losing point-to-point holiday destinations has little impact on the wider economy, but other British destinations have borne the brunt. Five years ago there were 124 flights a week from Edinburgh to Heathrow, 115 from Glasgow and 54 from Belfast, according to Innovata, a company that collects and analyses data for the airline business; now there are 109, 60 and 42. That has implications not just for the economy of the rest of the United Kingdom but also for its relationship to a capital from which it feels increasingly disconnected. Congestion at Heathrow also affects punctuality: more planes are over 45 minutes late from there than from Schiphol, Charles de Gaulle or Frankfurt. And the connections between London's European rivals and emerging countries are improving. Schiphol had 103 flights a week to the BRIC countries five years ago and has 129 now; Heathrow, 300 and 297. Dubai, Singapore and Hong Kong, London's main rivals a financial centre, all have spanking new airports with plenty of capacity. V. Shankar, Standard Chartered bank's chief executive for Europe, the Middle East, Africa and the Americas, is doing his job from Dubai, whereas his predecessors worked out of London. That's partly because the bank's business is increasingly in Asia, but also because of the infrastructure. Dubai's got a fantastic airport and a fantastic airline. The most important things for me are connectivity and communications. BAA wants to solve the problem by building a third runway at Heathrow. British Airways and all business groups support the idea. Londoners do not. Planes start roaring in over the city at 4.50am, and Londoners suffer more aircraft noise than the inhabitants of any other large city. The previous, Labour, government, persuaded by the business case, approved the runway. The Conservative-Lib Dem coalition, influenced by Tory votes (the transport minister's constituency is under the flight path) and Lib Dem environmentalism, cancelled it. Opposition to the third runway is one of the few subjects on which the coalition partners agree, though some Tories are nervous about antagonising the businesspeople who finance them. Mr Johnson wants a new airport in the Thames estuary, to the east of London. Foster Partners, a firm of architects, has produced a plan for one which it says would cost £50 billion, including transport links. But unlike the third runway, for which BAA and its banks would happily fork out, the estuary airport would be hard to finance. According to Michael Redican, managing director of global credit structuring at Deutsche Bank, money could be raised to build an estuary airport only if the government closed Heathrow. He reckons the cost of compensation to BA, bondholders and airlines would be around £20 billion, the transport links another £20 billion-30 billion and power supply a further £10 billion-15 billion. So even if the private sector were prepared to put up the £30 billion he thinks the airport itself would cost, the government would have to cough up somewhere in the region of £60 billion. In a country where up to now airports have been financed by the private sector, and in straitened times, that seems unlikely to happen. The government is conducting a review of airport capacity, and says that all options are under consideration - except the only one that seems feasible and useful, the third runway. That seems unwise. Londoners deserve their sleep, but it should be possible to placate them by reducing early morning flights. Without a hub airport that can expand, it will be harder for London to remain as connected as it needs to be to the rest of the world, and to its hinterland.