In London there are two types of taxi transportation. There are Black Cabs (hackney carriage) and private hire Minicab companies.

London Black Cabs

The drivers who ply the popular tourist routes can be some of the most knowledgeable and interesting people you will ever come across. Don't hesitate to ask them questions about London as most are only too happy to talk about the local area with you. However, there is a popular misconception about London taxi drivers. Contrary to popular belief taxi drivers don't know London like the back of their hands because "the Knowledge" test they sit only covers an area of 6 miles around Charing Cross.

The Knowledge is an interesting exam. Unlike many countries that have deregulated their taxi industries here in London a career driving a taxi is actually a REAL career choice! Stand on any street in central London and within 30 seconds (ok, that is a bit of a stretch!) you will see someone driving past on a scooter with a huge map on their handle bars as they drive around trying to prepare themselves for their knowledge test. This preparation can take years before the aspiring taxi driver has "the knowledge" required to become a certified taxi driver.

These cabs can be somewhat expensive for a long journey (London taxis are the most expensive taxis in Europe), but if you've got a group together going a short distance, it may end up being cheaper (as well as faster, and more pleasant) than taking the Tube. Much like in the USA, cab fares are metered and you can hail a Black Cab on most corners.

When it comes to tipping, 10% used to be customary but with the increase in fares most Londoners just round up the amount to the nearest pound.  Payment in cash is normal (drivers carry change) but a small number will accept the major credit and debit cards and charge an additional fee for doing so.  This can nonetheless be worthwhile for the long journeys.  The taxis can belong to one of more cooperatives, such as ComCab, which can also have their own credit card.  If they do, this card can be used only with member firms' taxis.

Hailing a taxi

The way to tell that a cab is free is to look at its taxi light on top of the car. If its turned on (it will be glowing yellow) then you can hail these taxis from the side of the street.   They cannot stop in intersections or in areas that are barricaded to keep pedestrians out of traffic, so move to a location where they can stop either before or after hailing the cab.

Don't be offended if they don't stop, they either didn't see you or didn't like the look of you! Drivers must, unless they have good cause, accept any hiring up to 12 miles (20 miles if starting at Heathrow Airport), or up to one hour duration, if the destination is in Greater London.  If they refuse to take you, it's within your rights to report them to the Public Carriage Office, so don't be afraid to be firm when requesting a long ride.

There are also a number of regulations that taxis must meet, one of them is that they must be able to carry a bale of hay (don't ask why) and they must also be able to turn on a sixpence (quite handy for narrow London roads). However, like the old Routemaster buses, the days of the London cab could soon be over as there are moves afoot to relax the taxi regulations and allow other types of cars to be used on the streets of London (the current cabs are mostly made in Coventry).

Black cabs also have a variety of passenger-controlled features, including a privacy/intercom system to speak with the driver, and fan and heating controls. However, there is no passenger air-conditioning, so in very hot weather a minicab may be preferable.

Minicabs

Minicabs are normal cars available for hire.  Anybody working as a private hire driver in London should have either a licence or a temporary permit.   There ar 50,000 minicabs in London and 22,000 taxis.  Reputable firms are easy to come by and you will always get a cheaper fare than you'd find with a Black Cab. Only Black Cabs are allowed to pick people up off the streets, minicabs must be prebooked by phone or at their office.  Minicabs are not metered always agree on a price when you make your booking.  If you order one by phone, make sure you get the firm you ordered by asked for the destination and your name.  Also make sure the licence is on display.  If you want to go with a minicab company that will actually know how to get you home, it's best to get a number from a native and call ahead of time.

Minicabs are perfectly safe if you pre-book. Their journeys have to be recorded at their office by law. You have the might of the Public Carriage on your side if there is a problem. NEVER get into a minicab that you have not pre-booked. You have no assurance that they are genuine.

Here is a selection of large reputable minicab companies covering different parts of London .Each one of these is an accredited member of the Licensed Private Hire Car Association (LPHCA) www.lphca.co.uk.

Car hire 

When it comes to renting a car in London, a simple phrase springs to mind: "Don't do it!" Not only can it be confusing to drive on the "wrong side" of the road, but it's quite costly as well.  Even if you get a good rate on renting a car, get ready for a shock at the pumps when you go to fuel up (called petrol in England and sold by the litre) and when you have to pay for parking.

Plus, there's fee that you have to pay when you drive into Central London, the "Congestion Charge." The Mayor created this fee in order to persuade people to use public transport instead of driving into the city. The goal is to help lessen congestion, as well as pollution, on London's roads.

The first time you enter a "charging zone" during the day, you pay £8, however you only pay the fee once for the day. And if you don't pay the charge by midnight it goes up to £10.  If you still haven't paid by midnight the following day it becomes a £100 fine (reduced to £50 if paid within 14 days), which can put a damper on any one's travels.  This charge is also payable if you drive in the Zone,ie thereis no need to cross the boundary to be liable.

Parking is something of a nightmare as well. Double parking is strongly discouraged, unlike in some American cities where it's almost as revered as an Olympic sport. If you do manage to find a metered spot on the street, be aware of all the signs nearby so that you don't come back to a hefty parking ticket left by a strict parking warden. On the other hand, parking garages (known as car parks) can charge outrageous hourly fees. With such an expansive public transportation system at your fingertips, you'd really have to be a bit nuts to want to rent a car and take to the maze that is London's streets.

That being said, if you are a little crazy and determined to figure out the labyrinth that is Central London by car, your best bet to find an affordable vehicle is to check with CARTRAWLER, CARHIRE3000, RENTALCARGROUP, DECODE CAR HIRE LTD.  All the usual suspects – Enterprise, Hertz, Alamo, etc. – are accounted for here if you have a specific company that you prefer.  Useful to visit the rental car brokers, as the deals of  major ( THRIFTY, AVIS HEATHROW, EUROPCAR, BUDGET, HERTZ HEATHROW, SIXT, BOOKING CAR RENTAL, NATIONAL, ALAMO ) and local car rental companies  (suppliers) are compared in one site. They offer online booking possibility, live support and 24 hours hotline. 

Be forewarned – check the fine print to make sure you know what kind of car you're renting. Mini or economy cars are notoriously smaller than their U.S. counterparts.

Renting a car to drive out of Central London, Heathrow or Gatwick would be difficult if you simply relied on your map reading ability - plan ahead of time, get good directions, and don't try it during peak travel hours.

Those with particular trouble navigating may want to rent a SatNav unit to put in the car. This little unit will speak directions to you and show you a clear map to guide you on your way. If you miss a turn and get off the route, the GPS Unit will recalculate and get you on your way. This unit can either be rented with the car rental company, or you can have one delivered to your hotel. If you do a search on the London Forum, you will find more information on this procedure.

Most cases for hiring a car you will need embossed credit card for the local deposit, passport, and driving licence. (sometimes international driving licence is required.)