The headline rule in one paragraph
Under TfL's current Hackney Carriage policy, a London-licensed taxi may not remain in service past the 15th anniversary of the date the vehicle was first registered as a taxi (not first registered as a car). On that anniversary, the vehicle's TfL licence cannot be renewed regardless of mechanical condition, MOT status, or owner preference. The driver has three choices: replace the vehicle with a TfL-eligible cab (in 2026 that is effectively the LEVC TX, with a small population of compliant TX4s still in service), surrender the plate and convert the vehicle to private use, or sell to a specialist buyer who handles the deplating workflow.
The 15-year clock starts on first taxi registration, which for nearly all working cabs is the date the vehicle was first plated by TfL. For a brand-new LEVC TX or TX4 the first-plated date is essentially the same as the first DVLA registration date; for a vehicle that started life as something other than a cab (rare in the modern fleet but historically common), the clock starts on the date of conversion to taxi spec, not the older car registration date.
What changed between the old 10-year rule and the current 15-year regime
Until 2017, TfL operated a hard 10-year limit on most cab makes plus a 15-year limit on a small set of low-emission models. The 10-year limit was tightened to push older diesels out faster. In 2017 the policy was rewritten alongside the ULEZ + zero-emission-capable (ZEC) regime: the 15-year limit became the universal age cap, and a separate ZEC requirement was layered on top, which meant that from 1 January 2018 no newly-licensed cab could be plated unless it met the ZEC criteria (effectively, the LEVC TX or a small number of approved alternatives).
The practical effect of the 2017 changes is that the active London Hackney fleet from 2026 onwards is split: existing diesel TX4s plated before 2018 are still allowed under the 15-year limit (most are now 8 to 13 years old and aging out gradually), and everything plated since 2018 is a LEVC TX (range-extended electric or full-electric depending on the production year).
If you bought your TX4 second-hand, the age limit is still measured from its first taxi registration, not from when you bought it. This is a frequent driver misunderstanding and it is unforgiving: a 2014 TX4 sold to its third owner in 2024 is still due to age out in 2029.
You can check your vehicle's first-licensed-as-taxi date through your TfL driver portal. The Vehicle Licence Number (VLN) on the licence plate sticker is also the lookup key in TfL's public Hackney vehicle register.
Common exemptions and edge cases (and why most do not apply)
The 15-year rule has very few exemptions. Wheelchair-accessible status is not one of them; ZEC status is not one of them; clean Euro 6 emissions are not one of them. The only routine extension mechanism is the rare case of a vehicle that has been off-road and unplated for a continuous period, where TfL may consider the off-road period when calculating the effective in-service age. This is case-by-case and not a route most drivers can rely on.
Heritage and ceremonial use is treated separately, with TfL allowing certain pre-2007 Hackneys to continue in restricted service under a Heritage Vehicle exemption. This applies to a very small population (about 200 vehicles in 2026 across the FX4, Fairway, and Metrocab fleets) and the routes available to a heritage-licensed cab are limited (no street hire, mostly weddings and corporate hires).
Cross-border licensing is sometimes raised as an option (running a London Hackney on a non-London plate after the TfL age-out). In practice the operational economics rarely work because the cab is then licensed in (say) Wolverhampton or Lewes and cannot legally pick up street-hire fares in London, only pre-bookings, which changes the entire business model. Some drivers do this; most do not.
The sell-or-extend decision drivers actually face
Most TX4 drivers facing the 15-year cut-off run the same maths: what is the cab worth today, what would a 2-year-old LEVC TX cost, what is the expected income over the next 3 to 5 years of full ZEC service, and how does the difference compare to the cost of switching now versus running the TX4 to its age-out date.
In 2026, a clean Euro 6 TX4 from 2015 or 2016 typically resales to a specialist buyer for £8,000 to £13,000 depending on mileage, plate validity, and condition. A used 2020 to 2022 LEVC TX with reasonable mileage (60,000 to 100,000 miles) sits in the £25,000 to £36,000 band depending on battery health and trim. The gap is real and not trivial to bridge, but the math becomes much more favourable when you factor in the operational savings (electricity at depot charging is roughly 25 to 35 per cent of equivalent diesel cost per shift) plus the fact that the TX4 has a hard 2 to 4 year remaining window before age-out, whereas a 2022 LEVC TX has 11 to 12 years.
Finance options have widened in 2026: TfL's Cab Trade Vehicle Grant scheme, the Mayor's electric-cab fund, and several manufacturer scrappage schemes for retiring older diesels are all active. None of them turn the maths neutral on their own but in combination they can shave £4,000 to £7,000 off the switching cost for an eligible driver. The eligibility rules are specific and worth checking against your individual circumstances before assuming you qualify.
If your TX4 has 18 months or less of plate validity remaining, sell now while the licensed-trade buyer network values the live plate. Resale value drops sharply in the last 6 months as the plate becomes near-worthless to a buyer who cannot transfer the remaining months.
What happens to a TX4 after age-out
An aged-out TX4 has three destinations: continental export (parts of Eastern Europe, North Africa, and the Middle East have active markets for diesel London-style cabs, both for licensed taxi service in those jurisdictions and for parts), out-of-London licensing (Wolverhampton, Sheffield and a handful of other councils still licence pre-2018 diesel hackneys), or conversion to private use as a working van-cab.
Specialist buyers handle all three routes routinely. The price difference between the routes is real but not enormous; an aged-out TX4 worth £4,000 to £7,000 in 2026 is typically a similar number whether it goes to export, to out-of-London licensing, or to a private buyer who wants the iconic shape for non-taxi use. The route is the buyer's commercial decision; the seller gets a single number that reflects the cleared value after the most likely destination.
Generalist buyers (instant-quote forecourts) often quote significantly less for aged-out TX4s, sometimes 30 to 50 per cent below specialist trade value, because they cannot easily place the vehicle into any of the three routes and assume they will need to wholesale it. A specialist buyer with active relationships across the three destinations does not face that uncertainty and prices accordingly.
What about LEVC TX? When does the age-limit clock start
The 15-year limit applies to the LEVC TX exactly as it applies to the TX4. A LEVC TX first licensed in 2018 will age out in 2033. The fact that the vehicle is electric, ZEC-compliant, and mechanically capable of significantly more than 15 years of service does not extend the licensing limit; TfL's age policy is age-based, not condition-based.
This matters because the early LEVC TX cabs (2018 to 2020 builds) are now 6 to 8 years into their 15-year licence life and the second-hand market is starting to price the remaining years rather than the chronological age. A 2019 LEVC TX with 9 years of plate validity remaining commands a different number than a 2020 with 10, even at similar mileage.
For drivers buying second-hand, this means the age of the vehicle is the single most important value lever after battery health, and a 2-year-old TX with 13 years of plate life is worth a clear premium over a 4-year-old TX with 11 years remaining, regardless of how the two compare on mileage and trim.