A licensed London taxi (Black Cab) driver is legally required to accept any fare provided the destination is within the Statutory Area (the Metropolitan Police District or the City of London) and the journey does not exceed 12 miles (or 20 miles if starting at Heathrow Airport). This is a condition of their license under the London Cab Order. However, there are specific legal exceptions. A driver can refuse if they have a "reasonable excuse," which typically includes the passenger being overly aggressive, visibly intoxicated to a dangerous level, or carrying items that might soil or damage the vehicle. If the destination is outside the Greater London boundary, the driver is not obligated to go, and if they do agree, the fare must be negotiated in advance rather than using the meter. In 2026, with the rise of digital "hailing" apps, these rules remain the backbone of the "Knowledge" of London, ensuring that the public has reliable, non-discriminatory access to transport within the city's heart.