The Conservatives' iron-clad discipline suffered several cracks last week as party members bickered behind closed doors over Brian Mulroney -- the former prime minister who divides them still.

MPs and senators feuded privately over the Harper government's treatment of the former leader as a public inquiry begins looking into his business dealings with arms dealer Karlheinz Schreiber. Some are now going public.

Sources in the Conservative caucus have told The Canadian Press that their meeting last Wednesday was pocked with bitter exchanges about the man who delivered the last Tory majority government.

Several MPs pointedly criticized the way Mulroney was being treated by Prime Minister Stephen Harper's staff.

A cabinet minister was heckled when she attempted to explain the PMO version of events to Mulroney's defenders.

One outraged Mulroney supporter strode into the caucus room and straight to the podium to address fellow Conservatives after consulting with the former PM by phone.

By the end of the altercation, the Conservative House leader glumly buried his face in his hands.

"It was an uncomfortable thing to see the family fight," said one Conservative member of caucus.

"We've had it out before from time to time -- over issues, like same-sex marriage, like the gun registry. But it's never personal. It's usually very collegial.

"It's strange to see us have that type of discussion."

The PMO set to work to downplay the caucus divisions even as the story was being written. At 4 a.m. Sunday. it issued a series of talking points to help orchestrate a response. Among them:

- "These stories don't relate to anything that ordinary Canadians care about."

- "The government stands by its decision to appoint the Oliphant Commission of Inquiry."

Unlike the more voluble Liberals, Conservatives rarely discuss what happens at their caucus meetings. But there was palpable unease when Mulroney loyalists stood to speak last week and that has now spilled out in public.

They voiced their displeasure after Harper's office actively sought out reporters to declare that Mulroney was no longer a card-carrying Conservative.

The prime minister has already ordered members of his government -- including those who consider Mulroney a personal friend -- to sever ties with him.

Harper was away last week at European summits. While the boss was on another continent, his Conservatives were uncharacteristically restive.

The prime minister had made it clear he wanted to keep a safe distance from Mulroney during a public inquiry into his business dealings.

But some Conservative MPs expressed indignation with how last week's phase of the plan was executed by senior party officials. They were particularly upset the news leaked out while Mulroney was ill, in a West Palm Beach, Fla., hospital with food poisoning.

The first to speak up was Lee Richardson, an Alberta MP who was once a young staffer in Mulroney's PMO and then ran successfully under him in 1988.

Then came Defence Minister Peter MacKay, speaking up for the man who had named his father to cabinet a quarter century ago.

Senator Gerry St. Germain, who was an MP under Mulroney, followed with more of the same. Finally, Senator David Angus moved to the microphone and announced he'd just spoken by phone with Mulroney from his winter residence in Florida.

The suggestion that Mulroney had asked to be stricken from any Conservative party lists?

"It's not true," Angus rumbled.

He said the former prime minister had been donating the maximum possible amount to the party, but simply told Senator Irving Gerstein several months ago that he wanted out of the Tory Leader's Circle.

Membership in that group earns big donors a lapel pin and an invitation to exclusive events. Given that he was persona non grata, Mulroney declared he wanted no part of Harper's 'circle,' his loyalists say.

But the Harper Tories reply that the ex-prime minister's membership lapsed three years ago, and that he specifically asked Gerstein to strike his name from any Conservative list.

It came as a shock to some of Mulroney's friends last Wednesday when they heard Senator Marjory LeBreton echo the government's explanation.

LeBreton was a high-ranking official in Mulroney's office; he later named her to the Senate, and for years they remained so close that she acted as his unofficial spokesperson on Parliament Hill.

Now a member of Harper's cabinet, LeBreton has respected the 2007 order from her new boss not to talk to her old boss.

And on the issue of membership, LeBreton told her colleagues at Wednesday's meeting, the new boss was right.

As she stood at a microphone in the middle of the room and repeated the explanation that Mulroney had allowed his membership to lapse, LeBreton was heckled.

Lee Richardson bellowed, "Says who?"

LeBreton's intervention met with scattered applause. So did the monologues by Mulroney's friends.

But most of the 150 people in the room simply sat in silence, or shifted uncomfortably in their chairs.

An unhappy House Leader Jay Hill lowered his face into his hands.

It was a vivid illustration of the awkward role Mulroney plays in the new Conservative Party of Canada, where he is a polarizing figure.

Some Tories revere him as the father of free trade, the statesman who battled apartheid, and the green prime minister who delivered the acid-rain treaty. To a few, he's even an old boss, family friend, or valued adviser.

To some others, he was the leader they loathed -- the one who inspired them to create the Reform party, and they want no association with questions about why Mulroney accepted at least $225,000 in cash from an arms dealer.

"Half the people in the room hated that man. They came to Ottawa (as Reformers) because of him," said one Conservative.

But last week offered proof that Mulroney still has more than a few friends in the Conservative caucus.