WINNIPEG - After a long battle to remain at the helm of Canwest Global Communications, Leonard Asper announced Thursday he has resigned as president and CEO of the crumbling newspaper and broadcast empire founded by his father.

The move, widely expected after Calgary cable giant Shaw Communications (TSX:SJR.B) won bankruptcy court approval to take control of Canwest's broadcasting assets, nearly severs the last Asper family tie to the Winnipeg company. Leonard's brother and sister, David and Gail Asper, resigned from the Canwest board last month, though technically the family still holds a controlling block of multiple-vote shares in Canwest.

In a brief note to Canwest staff, Leonard Asper -- the son of Canwest founder Israel (Izzy) Asper who died in 2003 -- expressed little emotion as he announced his departure as a "natural time for me to move on."

"This decision did not come without a lot of careful consideration," wrote Asper, whose own last-minute bid to retain some control over the company failed when Shaw's offer won approval.

"Taking this action now will also allow me to pursue other business opportunities and avoid any conflict of interest that I may have."

Asper, 45, will continue on as a consultant to Canwest until the restructuring process has been completed.

"As I embark on a new path, I will be taking with me many fond memories from my years as CEO, most of which centre on the inspiring and talented people with whom I was fortunate enough to work," Asper wrote.

Canwest's TV business will continue to be managed by Peter Viner and senior management at newspaper publishing and online operations will stay the same.

Though it rings with finality, Asper's resignation may not have been his swan song, said analyst Duncan Stewart, director of research and analysis at DSam Consulting.

"He's obviously doing the right thing and stepping aside," Stewart said.

"But it is worthwhile noting that in the history of companies emerging from bankruptcy (protection) with as many complicated moving pieces as we have in the Canwest story, there is still every chance in the world that there could yet be subsequent bids which Leonard is a part of."

Canwest (TSXV:CGS) owns the Global TV network and a number of major Canadian daily newspapers including the National Post, the Vancouver Sun, Calgary Herald, Montreal Gazette and the Ottawa Citizen. The company has been operating under protection from creditors since last year after it ran into trouble paying down a massive $4-billion debt racked up when Izzy Asper was at the company's helm.

Leonard Asper's exit was almost assured after he was involved in a failed bid last month for Canwest's broadcasting assets, which was led by his financial partner Catalyst Capital Group.

Shaw emerged from that process as the winner, and struck a deal to take control of Canwest's TV and broadcasting businesses. A number of suitors have come forward to bid separately for the newspapers.

Even before Asper lost that bid, he showed a determination to stick with the company. For months, he staved off filing for creditor protection by helping to secure numerous payment extensions with its lenders as it sold assets and streamlined operations to reduce costs and pay down some of the debt.

Derek Burney, Canwest's chairman, thanked Asper in a statement, citing his "years of dedicated leadership and unwavering commitment to Canwest."

"His vision and determination over the last decade has been instrumental in shaping the Canadian media landscape," said Burney, past CEO of pilot trainer CAE Inc. and a former Canadian ambassador to the United States.

Eventually, his efforts proved insufficient to overcome the company's debt problems, which began a decade ago with Canwest's $3.2-billion purchase of 13 major Canadian newspapers, 126 community newspapers, Internet properties, and half of the National Post from now-disgraced newspaper magnate Conrad Black.

The company also expanded its debt when it struck a deal to acquire the Alliance Atlantis specialty TV channels three years ago in a $2.3 billion deal financed mainly by Wall Street partner Goldman Sachs.

When Canwest filed for creditor protection last fall, Asper pledged to commit up to $15 million in the restructured company as part of an agreement with lenders intended to save the company.

That was before the company was forced to start searching for buyers of its broadcast and newspaper assets.

Several bidders have emerged for the newspapers, being sold under a separate but related court-supervised process. Three Canadian media veterans, headlined by former Canadian senator Jerry Grafstein, launched a bid in January for just the Post, the Montreal Gazette and the Ottawa Citizen.

Under that offer, Canwest would have to find someone else to buy the rest of their newspaper operations, which also include the Edmonton Journal, Victoria Times-Colonist and two Vancouver dailies, the Sun and Province. Canwest has said it believes selling the assets as a whole is a better option.

The Big Five Canadian banks, who are Canwest's senior secured lenders, have put in an initial bid of about $925 million to get the auction going. But they hope to get a higher offer of more than $1 billion or so they can get their loans repaid.

Victoria, B.C.-based Black Press, the small-market newspaper chain headed by businessman David Black, is also reported to be in the running for the Canwest print assets, though it has yet to make public any formal offer.

Another B.C. publishing outfit, community newspaper publisher Glacier Media Inc., is reported to be in the hunt for Canwest's smaller papers as is a group led by National Post chief executive Paul Godfrey.