Volkswagen should face corporate manslaughter charges for deaths caused by pollution from its cars, a former government advisor has said.
Stephen Tindale, also a former executive director of Greenpeace UK, said the company had "deliberately fiddled figures which killed people".
He said a class action was sensible and "should be winnable".
The German car giant has admitted it had used software in the US to provide false emission test results.
The firm's US boss said it "totally screwed up".
The company was approached for a comment on Mr Tindale's remarks.
In the UK, the company suspended the sale of 4,000 vehicles earlier this month - saying they may be equipped with the device that cheated tests in the US.
It confirmed 11 million of its vehicles worldwide had engines with the so-called "defeat device".
And it said almost 1.2 million vehicles sold in the UK were affected by the scandal.
Mr Tindale told Radio 4's Costing The Earth programme: "It is to me quite clear that they are guilty of corporate manslaughter. I would go further and say that as they deliberately fiddled figures which killed people they are guilty of corporate murder."