Already at sea, the Ten Network is more vulnerable than ever after yesterday’s sudden resignation of Lachlan Murdoch as chairman and the unwinding of a shareholder agreement between his private investment vehicle Illyria and billionaire James Packer’s Cavalane Holdings.

On October 20, 2010, Packer revealed he had bought a 16.5% stake in Ten for $258 million at $1.50 a share. Next weekend he invited Murdoch to Ellerston, the Packer family estate near Scone, and an agreement was reached that Murdoch would come in on the deal.

A month later, Packer’s stake had increased fractionally to 17.9%; on November 23 it was revealed Murdoch had paid $128 million or $1.37 a share (cost price less dividends received) for half of it, under an agreement which bound the two to work in concert. Just how Murdoch financed that investment has never been clear — there have been rumours that Packer may have helped out with a loan. Packer went off the Ten board and appointed Illyria’s Siobhan McKenna as his representative.

The mess Packer and Murdoch — along with Gina Rinehart, also roped into an investment — have made of Ten over the next three years has been well documented. After three CEOs, two capital raisings and lately the failure of a strategy to convert the Sochi Winter Olympics and Big Bash Cricket into increased market share, the network’s shares are worth 27c this morning. In ballpark figures, probably the better part of half a billion dollars has gone up in smoke. The ailing network now regularly rates below the ABC and Ten is mired in litigation with Seven over a failed attempt to recruit John Stephens as a programming head.

The elevation last night of Hamish McLennan to become executive chairman has raised eyebrows, partly because governance experts prefer non-executives to occupy the chair. McLennan is the only executive chair among the ASX100 who is not a company founder.

Proxy adviser Dean Paatsch of Ownership Matters says that’s not necessarily a concern for Ten’s minority shareholders, as Murdoch is counterbalanced by Ten’s other heavyweight investors, who sit round the board table. Ten’s minority shareholders are already “subject to their whims”, he reckons, so nothing’s really changed.

More importantly, however, there is a question of the continuing influence that Murdoch may have over McLennan, whom he hired. Murdoch had to go off the board of Ten, but will ACMA accept that Murdoch has no influence over McLennan, who is also chairman of the listed Realestate.com.au, in which News holds a 62% stake?

Both Lachlan Murdoch and Packer are now free to deal with their Ten stakes as they see fit. Speculation has been rife that News will bid for Ten — while News (and Lachlan himself) have expressly and repeatedly denied they have any such intention, yesterday’s announcement could pave the way for a deal to relieve Illyria of its stake.

It is hard to see Packer — whose strategy for the network has never been clear — as a natural long-term investor in Ten. And equally hard to see the share price recovering, with up to 17% of the stock overhanging the market.

Media analyst Roger Colman says with no loose talent available to run the network, Ten has only two options: import talent or merge with Foxtel, owned 50/50 by News and Telstra.

Yesterday’s announcement ensures takeover speculation about Ten will only intensify.