General Motors underlined its dire financial condition on Thursday as it reported an unexpectedly heavy cash drain in the final three months of 2008 and warned that Deloitte, its auditor, might cast doubt on its standing as a going concern.

The Detroit carmaker, dependent on government aid for survival, reported a fourth-quarter loss of $9.6bn, bringing the 2008 loss to $30.9bn. GM has racked up losses totalling $86.6bn during the past four years.