(Adds details, VW U.S. deal, UK industry body comment; refiled to correct preposition in penultimate paragraph)
LONDON, April 21 (Reuters) - Britain said on Thursday all 37 diesel car models it had tested out on the road exceeded the laboratory limits for polluting nitrogen oxides, but only Volkswagen had used so-called defeat devices to cheat tests.
The transport ministry examined cars from over 20 brands including major manufacturers BMW, Ford, VW and General Motors.
It tested 18 older cars against so-called Euro 5 standards for nitrogen oxide (NOx) emission levels and 19 newer ones against tougher Euro 6 levels, with all the vehicles recording readings above the legislative limit during on-road tests.
“It can be seen that all of the results are substantially higher than this limit, with the best results being about three times higher, and the worst about 10 times higher,” it said, referring to vehicles tested against Euro 5 levels.
Transport minister Robert Goodwill said carmakers had “not done anything illegal” as they only had to meet laboratory standards at present but that real-world driving emissions tests would be introduced from 2017.
Among the older models, GM’s Vauxhall Insignia hatchback recorded the highest NOx result of nearly 1900 mg/km, over 10 times the laboratory test limit whereas the crossover Peugeot 3008 had the highest emissions of the newer cars, almost 14 times the limit.
Britain launched an investigation into emissions after Volkswagen (VW) admitted to rigging U.S. diesel emissions tests in September.
A federal judge said on Thursday that Volkswagen and the U.S. Justice Department have reached a deal in principle to address excess diesel emissions in nearly 600,000 polluting vehicles that will include buyback offers and a possible fix.
Britain’s Department for Transport said only VW had been found to be using defeat device software to cheat tests.
“The vehicles tested in the UK programme showed no evidence of car manufacturers, apart from VW Group, fitting devices to defeat the approved emissions test programme.”
VW had previously said 1.2 million of its cars in Britain had been fitted with defeat devices and around 11 millions cars worldwide.
It saw its UK sales plummet from October with the first growth record in March when sales edged up 0.02 percent.
Britain said the re-testing programme cost 1 million pounds ($1.4 million) and that Germany would soon be publishing results of its own testing of 56 vehicles.
Britain’s automotive industry body the Society of Motor Manufacturers and Traders said meeting real-world testing standards could be costly for car firms but that all models approved from next year will pass on-road tests.
“This will require significant additional investment by manufacturers but will add greater transparency so consumers can be more confident industry is delivering on air quality,” a spokesman said. ($1 = 0.6979 pounds) (Reporting by Costa Pitas; Editing by Mark Potter, Greg Mahlich)