David Cameron is to go ahead with a reshuffle as early as this week amid private fury at the long-running inquiry into party chairman Caroline Spelman.
The Conservative leader has vented his frustration at the length of time a standards inquiry has taken to examine Mrs Spelman's financial affairs.
It is understood that Mr Cameron will not await the outcome of the investigation and will go ahead, whether or not she is cleared.
Former chancellor Kenneth Clarke is strongly tipped for a return to the Conservative frontbench, in the business brief. The rising stars expected to be promoted include shadow Culture Secretary Jeremy Hunt and Justine Greening, a junior Treasury minister.
Parliamentary standards commissioner John Lyon has spent nearly seven months investigating party chairman Mrs Spelman's taxpayer-funded payments to her nanny a decade ago. Mr Cameron had been expected to carry out a major reshuffle in October, after Gordon Brown's cabinet shake-up, but decided to await the outcome of the probe.
But the Standards and Privileges Committee, which publishes Mr Lyon's findings, has not even begun to compile its report, it is understood. However, sources have indicated that Mrs Spelman will not be punished.
Mr Cameron has told friends he is "extremely frustrated" at being made to wait so long.