Walk the ranks today and the maths of a fare often lives on glass: a booking app, a GPS track, an upfront price on a passenger’s screen. For many private hire drivers that phone is the whole commercial stack — job, navigation, payment, receipt. For hackney carriage drivers the sealed taximeter still rules the legal fare, even when Gett, Free Now or a local booking app sits beside it on the dash. The industry has not simply “swapped boxes for phones”. It has split into two metering cultures that share a common ancestor and a tangle of regulation.
Department for Transport figures for England as at 1 April 2026 show why the phone feels dominant. Of 417,300 driver licences, 71% were PHV-only. Taxi-only licences were just 7%. Private hire work must be pre-booked; the operator — increasingly an app — sets or quotes the price. Hackneys remain the sector where a council-controlled meter is still the public face of the fare. Understanding that split starts more than a century before Uber.
Before the box: fare books, landmarks and argument
Long before anyone invented a spinning meter, cities tried to pin down the price of a hire with paper. In London, the Hackney Carriage Act 1853 set statutory rates by distance or time. A one-horse carriage was sixpence for the first mile and sixpence a mile thereafter; time hire was two shillings for the first hour. The hirer chose distance or time at the start of the job. Drivers had to display fares and produce a book of fares on demand. Night rules limited when a driver could be forced to accept a time-based hire.
That was law. Practice was messier. Victorian passengers leaned on published cab-fare guides such as William Mogg’s measured tables, which priced thousands of runs from stands by actual measurement. Elsewhere, cities posted landmark tariffs — so much to the station, so much past a certain street — or charged by the hour. Disputes were common because the passenger and the driver often disagreed about how far they had come, which table applied, or whether waiting time had been fair. The fare was negotiated against a rulebook, not displayed as a running total.
Bruhn’s machine and the birth of the “taxi”
The word taxicab itself points to the fix. Encyclopaedia Britannica credits German inventor Wilhelm Bruhn with the taximeter in 1891 — a device that recorded distance and/or time so the fare could be measured mechanically rather than argued. Bruhn’s meters first appeared on horse-drawn droschken, counting wheel revolutions, with heavy attention paid to stopping drivers from fiddling the count. In 1897 a Daimler Victoria was fitted with a Bruhn meter — an early gasoline cab with a fare clock.
The idea crossed the Atlantic quickly. NIST’s history of meter testing recounts how New York businessman Harry N. Allen, stung by a flat $5 horse-cab fare for a short ride in 1907, imported metered French cars and launched the New York Taxicab Company at 50 cents a mile. By the 1920s meters typically took a cable from a front wheel; later designs moved to the transmission to cut tampering and clear space for front brakes. Calibration and sealing became part of the trade’s grammar: the meter was only as fair as the authority that tested it.
Britain’s hackney tradition absorbed the same logic. The meter became the public guarantee that the council’s maximum fare table was being applied trip by trip — flag fall, distance, waiting time, extras — visible to the passenger and sealed against casual alteration.
What a legal taximeter still is
UK law still treats a taximeter as a regulated measuring instrument, not a convenience gadget. Under the Measuring Instruments Regulations (MI-007), a taximeter works with a distance signal generator, measures duration, calculates distance from that signal, and displays a fare based on distance and/or time. It must support operating positions such as For Hire, Hired and Stopped, protect critical software and settings, and allow verification after it is in service.
That is why a dedicated unit from a maker such as Cygnus, programmed to a council tariff and sealed after calibration, is a taximeter — and a consumer smartphone running a fare estimator is not, for trade-measurement purposes. Hackney carriages are generally required to carry an approved, sealed meter. London’s taxi Conditions of Fitness still insist on a TfL-approved taximeter in an approved position, with receipts drawn from the meter in read-only form.
Private hire law runs the other way in the capital. Section 11 of the Private Hire Vehicles (London) Act 1998 bans PHVs from being equipped with a taximeter. That collision — apps calculating distance and time on phones — produced the defining case of the smartphone era.
Apps, GPS and the 2015 High Court line
In October 2015 the High Court, in a case brought with Transport for London, Uber, the LTDA and the LPHCA, declared that smartphones used in London PHVs are not taximeters. Mr Justice Ouseley’s formulation still shapes the trade: a taximeter is not a device that receives GPS in the vehicle, sends that data to a remote server which calculates a fare by distance and/or time, and sends the fare back to the phone. The phone may be essential to the pricing system; that does not make the vehicle “equipped” with a taximeter.
Outside London the picture is patchwork. Some licensing authorities allow PHVs to fit approved meters; others discourage or ban them; almost all leave PHV fares to the operator rather than a statutory maximum table. Pre-booked work may be a fixed quote, a company rate card, or an app’s dynamic price. The passenger’s guarantee is the booking contract and the operator’s licence — not a sealed wheel pulse.
So when drivers say “everyone meters on the phone now”, they are describing the commercial majority: PHV licences, app dispatch, GPS pricing. They are not describing a legal replacement for the hackney taximeter. Black cabs that take street or rank work still need the approved box. Many also use apps for pre-booked jobs, card payments and receipts — a dual stack that looks modern from the kerb and remains traditional in law.
How digital changed the feel of the fare
Even where the sealed meter survives, the journey to it has digitised. Electronic meters replaced mechanical clocks; calendar tariffs flip bank-holiday rates automatically; printers and card terminals talk to the meter; mirror-mounted displays free the dash for tablets. Dispatch radios gave way to smartphones. Passengers now often see an estimate or a fixed price before they sit down — then, in a hackney, watch the legal meter run if the job was not pre-agreed under local rules.
For app PHV work the psychology flipped again. Dynamic or “surge” pricing means the fare is set by demand as much as by distance. That can undercut a metered hackney off-peak and overtake it when the stadium empties. The meter’s old social bargain — same tariff for everyone who flags the same cab — coexists with a market that prices scarcity in real time.
The future of metering
Three pressures will shape the next decade.
First, metrology will stay hard. If a device is to be the legal fare for ply-for-hire work, it still has to be type-approved, sealed and auditable. Expect more digital MID-compliant meters with richer interfaces, better links to printers and payment, and tighter software sealing — not a free-for-all of any app calling itself a meter.
Second, booking and payment will keep migrating to the phone even when the fare clock does not. Hackney apps, account work and contactless are already normal. The political fight is less “meter versus no meter” than “who controls the tariff, the data and the complaint trail”.
Third, new vehicle types will test old definitions. Wheelchair accessible EV taxis, autonomous pilots and multi-modal booking platforms all need a clear answer to what the passenger owes and who is liable if the number is wrong. Regulators can keep the Bruhn idea — an independent, verified measure of time and distance — or lean further into pre-agreed digital contracts. London’s PHV smartphone ruling shows how carefully the law draws that line when technology races ahead of statute.
The taximeter began as a machine to end an argument on a horse-drawn hire. More than a century later the argument has moved: not whether distance and time should price a ride, but which device is allowed to do the summing, who seals it, and whether the majority of drivers — now private hire, now phone-led — still need a box at all. For hackneys the sealed meter remains the trade’s public scales. For everyone else, the future of metering already fits in a pocket — legally a booking tool, commercially the fare.