The figures have been published in Europe for three cars – the Peugeot 308, Citroën Grand C4 Picasso and DS 3 – and have been generated from a test procedure established with two non-governmental organizations, Transport & Environment (T&E) and France Nature Environment (FNE), and audited by Bureau Veritas.

The cars were driven on public roads near Paris (15.6m miles urban, 24.7 miles extra-urban, and 19.3 miles motorway) and under real-life driving conditions, notably with passenger and luggage loads, road gradients and use of air-conditioning systems.

The figures for the models were rated as 56.5mpg for the Peugeot 308, 50.4mpg for the Citroën Grand C4 Picasso and 57.6mpg for the DS 3 – similar to consumption measured via customer surveys but down significantly on the official combined figures.

The initial measurements are comparable to those made by customers obtained from independent customer surveys and have been welcomed as showing that that the procedure conducted with Transport & Environment is scientifically robust and representative of a typical driver.

Before summer 2016 PSA will release official real-world fuel consumption figures for 30 Peugeot, Citroën and core DS models.

Greg Archer, clean vehicles director at Transport & Environment, said: “The test developed with PSA Peugeot Citroën is reproducible and representative. It confirms the fuel consumption of a tested model by a typical driver in real-world driving conditions. This test proves that the on-road tests are reliable and can be used to measure real CO2 emissions. This should become the benchmark for all carmakers advertising their vehicles’ fuel efficiency.”