How to ensure there's a black cab when you need one on a wet night

London's black-cab drivers occupy a particular place in London's image. Alongside many other great institutions, they are praised and disparaged in almost equal amounts but they are rarely ignored. So it is unsurprising that the debate about the future of London's cabbies quickly arouses strong emotions even outside the capital.

London's black-cab drivers occupy a particular place in London's image. Alongside many other great institutions, they are praised and disparaged in almost equal amounts but they are rarely ignored. So it is unsurprising that the debate about the future of London's cabbies quickly arouses strong emotions even outside the capital.

Paul Barker, Senior Research Fellow at the Institute of Community Studies, this week launched a broadside on the black-cab trade in which he coherently argued that the black-cab driver is an overprotected species: "Black cabs are one of those classic British institutions - like the BBC and the NHS - which are claimed to be 'the envy of the world' but which, oddly, no one imitates."

The biggest complaint levelled at London's black-cab service is that there are simply not enough cabs about when you want one. If it's raining, or if it's late, then the common problem is that you just can't find one.

However, we should not throw the baby out with the bath water. Taxis are a vital part of London's integrated transport network. They form a unique link between other forms of public transport, fulfilling demands that cannot be met by the bus, train or tube; especially late at night. Licensed taxis ("black cabs") and currently unlicensed private-hire vehicles ("minicabs") can fill gaps not served by scheduled public transport.

In central London, taxis make a valuable contribution in enabling short trips to be taken when time is at a premium, especially by the business community. They are only hampered in this by the appalling levels of congestion in the city, which also make bus journeys a nightmare. Many women feel safer using black cab services, which take them door-to-door at night. London black cabs are also the only form of social transport in Britain that is 100-percent wheelchair accessible.

There are about 20,000 licensed taxis in London, generally operating where demand is highest - predominantly central London and Heathrow airport. It is estimated that there are 85m taxi trips a year in London. Licensed taxis and their drivers are regulated for quality, but not for quantity, by the Public Carriage Office (PCO), part of Transport for London (TfL). It is estimated that there are also 40,000 minicabs, which operate predominantly outside central London, and undertake 70m trips a year.

The Private Hire Vehicles (London) Act 1998 provides the legal power for a system of licensing to be applied to minicabs. Draft regulations have been published that will enable the PCO to regulate minicabs, including operators, vehicles and drivers. The poor quality of many minicab services will need to be tackled as a prerequisite to expanding their role but it is clear that particularly in outer London and, in the small hours, in central London, there is a role for a more regulated mini-cab industry.

With TfL being responsible for the licensing of taxis and, now, minicabs, there is an opportunity to tackle some of these fundamental issues. I am determined to enhance the service provided by the cab trade and I want to make it clear that I do not think that the institution of the black cab is an anachronism. It's true that you can more easily hail a yellow taxi in New York than a black cab in London. But when you get a black cab, they do at least know where they are going. I have heard horror stories of friends who have been driven around New York by taxi drivers who simply did not know where they are going. Ask any business person whether they want to fumble around with an A-Z on their way to a meeting, or whether they want their cab driver to speed them to their destination on the shortest possible route, and you do not have to wait for the reply.

At the core of this is "the knowledge" - the famously tortuous training that all black-cab drivers have to pass, ensuring encyclopedic knowledge of London's streets. It is proudly defended by the trade - and rightly so - and should not watered down.

I have found that there is widespread concern among cabbies themselves about the lack of black cabs after 11 o'clock at night. The simple fact is that the main problem with black-cab availability is economic. Demand currently massively outstrips supply, and it simply does not make economic sense for most cabbies to work late at night. They can get just as many - if not more - fares during the day when they can work a comparatively normal nine-to-five existence. If we are tackle the supply of black cabs at night then we will have to address the economic problem.

First, the black cab must be treated as part of the public transport system for the purposes of moving people about London. For that reason I have decided to exclude black cabs from paying the proposed congestion charge. Second, we should review the numbers and effectiveness of the current cab ranks so that all of the major transport termini are properly served by the trade.

Finally, I have already said I am prepared to consider a combination of measures to increase supply. One part of the package is that of making it more worth the black-cab driver's while to work late. I want Londoners to consider whether they would be prepared to pay more for late-night fares in order to make the late shift attractive. At the moment it is 90p extra per trip for working after midnight but - for example - a ?2 surcharge would probably boost the numbers. Drivers would make more money as part of what might be termed an "unsociable-hours tariff".

But as part of the same package, the cab trade needs to consider whether the current administration of "the knowledge" system is holding up the numbers of cab drivers who qualify. Without watering down the knowledge at all, we should consider whether or not there are ways to increase the supply of drivers. For example, are there enough examiners to see everyone who is ready to take the test? And as the London Taxi Board has also urged, we should look at encouraging new entrants to the industry to apply for licenses in areas of London currently poorly served by the black-cab trade.

The black cab is a symbol of London in much the same way as Nelson's column. It's future should be guaranteed as part of the mayor's transport strategy. And, yes, you should be able to get one after 11 o'clock at night.