There definitively is a difference- and it's no small one !!

MiniCabs are not allowed to be flagged down in the street. The officially called Private Hire Cars and they have to be pre-booked by you via their Control Centre. The problem with them in London is the fact that most of them are run by questionable companies, often time lacking the right kind of insurance which is there to protect you in case of problems. In addition, the cars are often less than roadworthy and the drivers do not require any special training what so ever to carry out this business. This is all a far cry from an official London Taxi, who's offical name is Hackney Carriage ! Those drivers are highly trained, as they have to get through what is commonly called "The Knowledge". For those not in the know (or without the knowledge), it's the exam that London taxi drivers must undertake to qualify to drive a black cab. It's basically a comprehensive test of someone's knowledge of streets within a certain (rather large) radius of Trafalgar Square.

Most of the prospective cabbies learn the Knowledge while riding around London on a scooter, generally on a Sunday with an A-Z map strapped to the handlebars.

Also, if you ever thought that those London Cabs are an antiquated part of motoring history, only English could still stick to in times of modern motoring, you would be surprised to learn the technology that is built into this purpose built passenger carrying vehicle ! These vehicles are really built for the purpose of what they are supposed to do, which includes being able to carry people and their luggage from point A to point B on the quickest, with you consent and only then not always the shortest, route in safety. These vehicles also effortlessly are capable of carrying Disabled in their Wheelchair, as they have built in Wheelchair ramps and floor fixing points.

Taxis in London are highly regulated and controlled by official bodies and all Taxi drivers must be in possession of a valid Hackney Carriage License.

On top of it all, the pricing is also regulated and all London Taxis carry a calibrated Meter, clearly displaying the incurred cost. This is not true for those MiniCabs, who have no meters, calibrated or not, fitted and who, as I found, try to overcharge out of towners on a regular basis.

Having in the past tried both modes of transport, I usually found that the London Taxi charges a lower prices anyway.