US - Energy Secretary Chris Huhne finds out later whether he will face charges over claims his ex-wife accepted a penalty for speeding on his behalf.
Director of Public Prosecutions Keir Starmer will announce his decision in a televised statement at 10:00 GMT.
Essex Police have been investigating the allegations against Mr Huhne, dating back to 2003, for eight months.
The Lib Dem denies the claims. Court action would end his cabinet career, the BBC's Nick Robinson understands.
Should Mr Huhne be forced out, Business Minister Ed Davey is likely to replace him with fellow Lib Dem Norman Lamb stepping into Mr Davey's shoes, our political editor said.
"Of course, if no charges are brought Chris Huhne will continue in his job," he added.
The Sunday Times recently handed over details of emails relating to the case to the police.