Tory education spokesman David Cameron has said he is "contemplating" entering the race to be his party's next leader.
David Cameron was a former adviser to Michael Howard.
The 38-year-old also said he backed Michael Howard's plan to stay on as leader until October and denied he was already starting his bid for the job.
On Wednesday, Conservative MPs, voting on eight different options on how to choose a new leader, failed to back Mr Howard's preferred plan.
Instead they opted for MPs alone, not party members, choosing a leader.
Mr Cameron told the Today programme: "I didn't vote at all. I think anyone contemplating taking part in this contest should probably not vote on the new system."
He said a speech he was making later on Thursday was one of the "early salvos" of his time as shadow education secretary, not the opening of a leadership campaign.
He will tell the Policy Exchange think tank in London: "In opposition - every bit as much as in government - politicians need to set out what they believe in, what their goals are, and what their compass will be.
"If you don't - and if you don't stick to them - you will get buffeted from one issue to another."
The current leadership system, brought in under William Hague, sees MPs choosing their two favourite candidates, with the party membership across the country then choosing between those two.
This system has been used just once, when Iain Duncan Smith beat Kenneth Clarke to the leadership in the vote of party members.
Mr Howard's preferred option would have seen the final choice returned to MPs, although party members would have had a vote to sift down candidates.
MPs voted for a system under which Conservative activists would be consulted, but with MPs making the final decision on who should be leader.
Mr Cameron said this was "basically" the same as that proposed by Mr Howard.
Michael Howard is hanging on until later this year
He said he did not back those calling for Mr Howard to quit now, saying the party needed time to debate its approach.
That approach was echoed by fellow frontbencher Theresa May, who said the party was "in danger of missing the point" if it focused on personalities rather than how it needed to change.
Mrs May refused to say whether she would be a candidate but said it would send the wrong signal to voters if MPs did not give party members a say.
Some MPs are frustrated by the lengthy leadership timetable and fear it will turn the autumn Conservative conference into a contest.
There are rumours that lists of names being collected to force a confidence vote which would speed up Mr Howard's departure.
Other MPs insist they should respect Mr Howard's timetable.
Mr Cameron has enjoyed a rapid rise and joined the shadow cabinet in September last year.
His previous positions have included head of party policy co-ordination - now a front bench post.
He was also an adviser to former Tory Chancellor Norman Lamont and subsequently to Mr Howard when he was home secretary.
Other possible candidates in the frame for the leadership include: David Davis, Kenneth Clarke, Liam Fox, Alan Duncan, Tim Yeo and Sir Malcolm Rifkind.