Energy Secretary Chris Huhne is about to face his moment of truth as prosecutors reveal whether he will face charges for allegedly dodging a speeding penalty.
The announcement, which follows an eight-month police investigation, is due to be made in a live televised statement on Friday morning by director of public prosecutions Keir Starmer QC.
Any decision to proceed with the case is expected to spell the end of the Liberal Democrat's Cabinet career - although he has repeatedly refused to confirm that he would quit.
His ex-wife, economist Vicky Pryce, is also set to learn whether she will be charged. The potential offence could be perverting the course of justice.
The alleged incident dates back nearly a decade, but only emerged after Mr Huhne admitted an affair with PR adviser Carina Trimingham in 2010 and ended his marriage.
The Sunday Times reported that he had been caught speeding in Essex while an MEP in 2003. However, he is said to have escaped a driving ban by persuading Ms Pryce to accept the penalty points on his behalf.
Essex Police launched a formal probe in May, led by a detective chief superintendent, and the couple have been interviewed by officers twice.
Mr Huhne has repeatedly denied any wrongdoing, and both Lib Dem and Tory colleagues have expressed support for his remaining in post during the investigation.
The CPS decision was delayed by a court battle to obtain key emails from the Sunday Times, believed to be between its political editor and Ms Pryce, but the newspaper finally handed over the crucial documents at the end of last month.
It is understood Mr Huhne will be told of the decision shortly before it is made public.