Michael Howard has made his pitch to become the next Conservative leader.
Howard wants a broad coalition
Tory MPs greeted his campaign launch with cheers at a news conference in central London, where Mr Howard said he wanted a party "for all Britain and all Britons".
The ex-home secretary said he wanted to use talent from all wings of the Tory party, and later held talks with former chancellor Ken Clarke.
Mr Howard is already the frontrunner to succeed Iain Duncan Smith, who was ousted by Tory MPs in a narrow confidence vote defeat on Wednesday.
Rivals stay out
Several leading Tories had urged Mr Howard to stand, raising the chances that he could have a clear run at the leadership, with no contest at all.
Shadow deputy prime minister David Davis, shadow trade secretary Tim Yeo and shadow foreign secretary Michael Ancram have said they will not contest the post with Mr Howard.
On Thursday night former Defence Secretary Michael Portillo, who had already said he would also not stand, endorsed Mr Howard's leadership bid.
Shadow health secretary
Shadow home secretary
Shadow deputy prime minister
Shadow foreign secretary
Shadow trade secretary
But he told BBC One's This Week programme he did not expect to be asked to serve in the shadow cabinet were he to win.
Theresa May has also ruled herself out, according to her office, because as party chairman she wishes to remain neutral.
Mr Howard said the party had begun to unveil promising policies but was still "in the foot hills" of its ascent.
And in the wake of the recent Tory infighting, he continued: "There will be no place for ancient feuds or ranking discords."
"I will lead this party from its centre," he said. "I will call on the talents of all in the party and the party will expect all to answer that call."
Mr Clarke is thought unlikely to join the leadership race himself and Mr Howard said he had much more in common with his "good friend" than divided them.
"I shall be discussing with Ken the best way in which we can work together for the future of our party and the future of our country," said Mr Howard.
Later, Mr Clarke was said to be still undecided after their talks, but Howard campaign manager Liam Fox told Sky News it was "perfectly reasonable" for him to go away to consider his position.
Mr Howard pledged to offer a "new kind of politics", giving credit to the government where it was due and not greeting its failures with "gleeful pleasure".
There would be "rigorous honesty, measured criticism, realistic alternatives - only that way can we revive people's trust in politics", he said.
People in deprived areas should not be left behind, he argued, saying: "There can be no 'no go' areas for a modern Conservative Party."
On specific policies, he said he would not be afraid to argue for lower taxes and said he would be internationalist while still raising concerns if the European Union was "too intrusive."
Mr Howard's camp boasts the support of 90 of the 165 Tory MPs, with Mr Ancram saying earlier he would not run as long as Mr Howard remained the only candidate when nominations close at noon on 6 November.
Not all potential candidates have yet declared their hand.
One source has told BBC News that two MPs are taking soundings among the party's right wing about whether to enter the contest.
Nominations now open for leadership race
6 November: Nominations close
11 November: First leadership ballot of MPs
Iain Duncan Smith remains caretaker leader until successor chosen
Tory MPs voted to oust Mr Duncan Smith by 90 votes to 75 in a confidence vote on Wednesday afternoon after months of speculation about his position.
In a speech on Thursday night, Mr Duncan Smith said: "I very much hope that - as tonight seems likely - my successor is chosen
quickly so that we can all get behind the leader."
Prime Minister Tony Blair, Mr Howard's old adversary from his time as home secretary, argued that under his leadership "there will be a real policy divide" between the Tories and Labour.
Mr Howard has said that if he is the only candidate, he wants his named endorsed by grass roots Tory members.
If there is more than one candidate there would be a leadership contest which would last a number of weeks, culminating in a vote by Conservative members across the UK.