Unbooked minicabs are illegal. You may be approached by minicab drivers seeking passengers or offering a service; avoid this as these are unsafe, unlicensed, uninsured and illegal and you put yourself in danger if you use these services.
Only taxis (black cabs) can be stopped by customers and can pick up off the street.
Booking your minicab with a licensed minicab company guarantees that your trip will be carried out by a licensed driver in a licensed vehicle. It also means that a record is kept of your journey, your driver and the vehicle used. Therefore, in the event of any problems, the driver can be traced.
Only taxis (black cabs) can be stopped by customers and can pick up off the street. Even minicabs lined up outside pubs and clubs are breaking the law if they accept your fare without a booking being made first. Many clubs have licensed minicab operators inside who can take your booking. Check with staff to see if a minicab service is available.