24 Hours Mini Cab Service
Gatwick, Heathrow and Luton. Airport pick and drop specialist.
http://www.londonradiocars.com/onlineCarBooking.asp

London Taxi prices - London Airport Transfers
You can book a taxi transfer from any of London's airports, the driver will be waiting for you in arrivals and transfer you direct to your hotel or destination of choice. Our fees include all waiting time and any other charges that the driver might incur whilst waiting for you. We no longer need to include waiting time for London airport pick-ups as we are able to monitor your flight from start to finish.
http://www.londontaxitour.com/

New Century Cars - A fully Licensed Taxi Cab Service
15 minutes from major London airports Gatwick and Heathrow by Taxi cab. 7/9 seat Luxury Mercedes taxi cabs. Corporate taxi cab accounts. Prestige cars at taxi rates. Secure and safe.
http://www.newcenturycars.co.uk/html/taxi_service.html

Premier Airport Cars
We specialise in transfer services from and to Heathrow Airport, Gatwick Airport, London City Airport, Stansted Airport and Luton Airport. For your security and piece of mind, Premiercars are fully licensed by the PCO (Public Carriage Office).
http://www.premierairportcars.com

Skyport Cars
Taxi and Minicab to and from London - Heathrow airport, Gatwick and Stansted.
http://www.skyportcars.com/

Spright - Airport Transfers - Executive Cars - Chauffeur & Taxi
Spright specializes in airport transfers, we have cars at the major airports such as Heathrow, Gatwick and Birmingham virtually every day. Whether your trip is for business or pleasure Spright can offer you a quality, competitively priced “chauffeur” service to any UK airport.
http://www.spright.co.uk/airports.htm

5% Off your Airport Transfer
Securely book your UK airport transfer taxis to and from the five major London airports - Heathrow, Gatwick, Stansted, Luton and London City, online and get 5% Off.
http://www.totallyairports.com