The European Union’s top environmental official alerted his colleagues that motor manufacturers were manipulating European emissions tests more than two years before US authorities uncovered widespread cheating by Volkswagen, according to internal EU Commission documents.

Despite the warning from Janez Potocnik (pictured), the then EU environment commissioner, Brussels did not take swift action to crack down on the practice but instead left in place an earlier plan that allowed the emissions loopholes exploited by VW to remain through to 2017.

VW last month admitted, in response to the US investigation, to using an illegal piece of software in its diesel engines to cheat in tests for nitrogen oxide (NOx) emissions.

In negotiations this month, the commission and EU nations considered giving carmakers another two years to fully comply with more robust tests that would force cars to meet EU limits on NOx emissions, allowing them to be phased in through 2019.

The documents show the manipulation of emissions testing by carmakers was widely known at the EU’s highest levels much earlier than previously believed. – The Financial Times Ltd