Embattled German carmaker Volkswagen said Thursday that the global pollution-cheating scandal it has been engulfed in since September was the result not of a one-off error, but a series of mistakes dating back to 2005. 

The scandal, which broke in September when VW was forced to admit that it had installed emission-cheating software into 11 million diesel engines worldwide, was "not attributable to a one-off error, but an unbroken chain of errors," VW supervisory board chief Hans Dieter Poetsch told a news conference, adding that the affair dated back as far as 2005 when the German group launched a massive new diesel offensive in the United States.