Backed up by a report prepared his investment banker ally, Bruce Wasserstein of Lazard, Mr Icahn is expected to argue that Dick Parsons, Time Warner’s chairman and chief executive, has destroyed shareholder value since taking over less than four years ago.

"Dick Parsons says he’s frustrated by the stock price," Mr Icahn said at an investor conference last week. "He should look within himself. The problem is him."

That message will likely be repeated soon after 3.30pm local time today (8.30pm London time). Mr Icahn is also expected to tell his assembled audience that Time Warner’s portfolio of assets does not make sense for investors.

Listeners tuned in to a toll-free call and webcast can look forward to hearing how Time Warner’s management only plan for the short term, and why the media conglomerate should return more cash to shareholders.

The Lazard-prepared report, said to run to more than 400 pages, forms the key part of Mr Icahn’s attempt to win support for an alternative group of directors at a shareholder vote in the spring. The investor, who speaks for just over 3 per cent of the company, has struggled to gain for popular support with his campaign so far but will be hoping that today’s conference will bolster his position.

Mr Icahn has already called on the company to spin off 100 per cent of Time Warner Cable and to buy back $20 billion in shares. Today’s document is expected to go further -- most likely calling on Time Warner to break itself up into its four constituent divisions.

Supporters believe a full breakup of the group would help unlock shareholder value because the company does not have a clear profile on Wall Street, meaning that it is attractive neither to growth nor to value investors.

The rebel shareholder’s main gripe is that the stock has underperformed many media peers since Mr Parsons’ appointment in 2002, a year after Time Warner’s disastrous merger with America Online. Supporters claim that ownership of AOL means Time Warner shares should be measured against fellow internet companies such as Yahoo! and Google, both of which have risen fourfold. Time Warner shares shows a loss for the period.

However, critics of Mr Icahn argue that comparisons with pure-play internet companies are unfair, as Time Warner’s portfolio of businesses are under-invested and at risk from technological change.

If Mr Icahn is to win over shareholders his breakup plan will, somewhat perversely, have to go some way to appeasing these concerns.

Time Warner today said it would sell its Time Warner Book Group to France’s Lagardere for $537 million. But that still leaves a publishing empire which could be seen as too low-growth for a stock market flotation. And at around $13 billion it would be too expensive to be purchased by rivals such as Pearson and McGraw Hill.

The group's $9.5 billion cable business could not be sold to a competitor as the US competition regulator would never allow it. A market flotation would be possible, but it would be a difficult sell a time when other cable stocks have sunk. Investors would also have to be convinced that there is no need to pour yet more money into new infrastructure.

For AOL, Google's recent purchase of a 5 per cent stake provides an implicit value of $20 billion. Mr Icahn’s camp have suggested in the press that more value can be extracted via merger with an internet portal – but not Google or Yahoo. That would leave the only feasible union partners as Microsoft or -- more likely -- Barry Diller’s InterActiveCorp.

But it would be open to question whether either would be prepared to pay a premium for an internet service provider with a falling subscriber base and an unproven advertising model.

Whatever Mr Icahn says today, Mr Parsons currently holds the upper hand at least in terms of the share price.

Last week, Time Warner shares rose more than 6 per cent in reaction to better-than-expected results, as well as interest from a Dubai investment fund. The fund, which is bring advised by Mr Icahn, has taken up to $2 billion of exposure to Time Warner shares via derivative positions.

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