BLACK CAB RETROFIT: TfL silence putting approved TX4 Euro 6 retrofit in jeopardy, says supplier
- Perry Richardson
- 2 hours ago
- 2 min read
A retrofit emissions upgrade for London’s TX4 taxis, approved by Transport for London in July, is now at risk of being withdrawn after the supplier said it has yet to receive confirmation on how the modification will affect vehicle age limits.
HJS Emission Technology said its project cannot continue without a formal response from the regulator before the end of the year.
HJS confirmed in July that its Euro 5 to Euro 6 retrofit system for the TX4 had secured TfL approval following emissions testing at Millbrook in April. The upgrade was regarded as a long overdue option for cab owners facing the high cost of replacing older diesel taxis, offering a compliant path for some vehicles to continue operating within the capital’s licensing rules.
In a statement issued on 9 December, HJS said TfL had still not set out how a retrofitted TX4 would be treated under existing age limit policies. The firm said this gap leaves operators unable to plan vehicle investment or assess whether the upgrade would deliver meaningful operating life beyond the current limits imposed on older cabs.
HJS warns its newly approved TX4 Euro 6 retrofit scheme may be abandoned after Transport for London fails to clarify age limit implications.
The company said its assumption, based on the lack of communication, is that TfL does not intend to permit any age limit extension linked to the retrofit. Age limits have been central to taxi fleet turnover in London, influencing when drivers must either replace or exit vehicles. Without assurance that Euro 6 compliance will translate into additional years on the road, demand for the retrofit would be negligible.
HJS warned that if TfL provides no clarity before the end of December, the project will be closed and suppliers and customers informed. The firm added that the decision would be driven entirely by regulatory uncertainty rather than technical issues, noting that the emissions upgrade already holds TfL approval.
The uncertainty comes at a time when many London cab drivers are navigating significant capital costs linked to vehicle transition. Retrofit options can help keep drivers reaching the end of their careers in the trade by minimising the cost burdens before planned retirement, but only when regulatory frameworks give drivers confidence about the length of time their vehicle will become compliant.
A TfL update on how the retrofit will interact with age limits is still outstanding. It remains unclear whether any guidance will be issued before year end.
A HJS Emission Technology spokesperson told TaxiPoint: “TfL approved the HJS emission upgrade from Euro 5 to Euro 6 for the TX4 on the 1st of July 2025. As of today, 9th December TfL has not issued any communication on the age limit policy changes that should become applicable to a taxi that has been retrofitted to Euro 6 emission.
“Therefore we must regretfully conclude that it seems TfL has no intention of permitting the emission upgrade.
“Should no communication be received from TfL by the end of 2025, we see no alternative other than to close the project, and inform our suppliers and customers, that the project will not continue due to factors outside the control of HJS.”
TfL have been approached for comment.
