After discussing this in other forums I though I had better put this as a seperate Topic.
After a rather nasty experience in august I thought i would let poeple know about this.
If you come to London and you use or are thinking of using any sort of transfer, cab, Taxi, limo service then you need to be aware of these facts.
All CAR services of this type HAVE to be licenced, if they are not, then tey are operating illegally!!!.
And as i discovered to my cost this means that they wont be insured .
Now London Black Taxis have the licence details on a white plate on the rear of the vehicle, also the driver MUST have a green Blue or Yellow badge with his licence details on it.
If there is no white plate, no badge or NO METER in the TAXI, dont get in.
Licenced black (although they come in different colours) are easy to spot, they have a yellow TAXI light on them, like NY cabs.
London also has lots of private transfer companies like this one
http://www.airport-transfers-uk.com
These companies also have to be Licenced, but their isnt anyway of telling from the vehicles or the drivers if they are, the only way to check is to go here
http://www.londontransport.co.uk/pco/ph_ops_list.shtml
If the company you are planning to use isnt listed DONT TOUCH THEM.
Also be careful of travel portals that offer airport transfers in London, they may be using illegal companies and not even be aware of it.
If the company isnt based in London, then the licence details are hard to check, but THEY STILL have to b licenced to carry passengers.
When you are in London and you ask your hotel to get a cab for you, MAKE SURE they use a licenced company.

The Mayor of Lodon is currently running a campaign to warn people about unlicenced companies, but the thought occured to me, what about people from outside of London that come from abroad, they wont know until is too late.