David Davis stood aside from the Tory leadership race to avoid a contest that would have crippled the party, he said.
Mr Davis said he believes he could have won a leadership vote
Within minutes of it emerging that Tory MPs had voted to oust Iain Duncan Smith, Mr Davis announced his backing for ex-home secretary Michael Howard.
Mr Davis denied he had a deal with Mr Howard although he said he informed him of his decision before going public.
Other senior Tories swiftly lined up to back Mr Howard raising hopes that a damaging election could be avoided.
Mr Davis - who is currently shadow deputy prime minister - said he had met Mr Howard an hour before it was announced Mr Duncan Smith had lost the confidence ballot by 90 votes to 75.
He told BBC Radio 4's World at One programme: "It was a last-minute conversation just to make sure that he knew what I was doing."
"At the weekend, when all the papers were writing about potential challenges
to Iain, I started to think about the consequences beyond that," he said.
"The Tory Party's biggest handicap in recent years has been divisions,
faction fighting, in-fighting. It has stopped us being able to get our message
"I just came to the conclusion that the prospect of a hard-fought leadership election would actually make that worse, not better, and would leave the party
with scars that would probably cripple it in the run in to the next General Election.
"I also came to the conclusion that if I did what I did last night - announcing frankly that it was not a good idea to have such a battle - I, by myself, might be able to bring that about."
On Wednesday when he made his statement, Mr Davis said his decision to "step aside" came despite receiving enough support to suggest he could win a leadership battle.