By Jeremy Scott-Joynt BBC News business reporter

Lachlan Murdoch had been seen as the most likely heir

The departure of Lachlan Murdoch from News Corp, the international news group built by his father Rupert, leaves his younger brother James as the sole scion of the dynasty still in an executive position.

The smart money is therefore on James, now 32, taking over from Rupert Murdoch when the tycoon finally steps down from News Corp's helm.

When that will be, of course, is an open question. The elder Mr Murdoch may be 74 years old, but is married to a woman 40 years his junior, has two small children, and shows no signs of flagging.

Next in line

When the time does come, there seems little doubt that some form of Murdoch succession will be assured.

The Murdoch family holds about 30% of News Corp's shares, but nonetheless wields control over the group.

Rupert Murdoch's grip was evident in 2003, when he manoeuvred James into the chief executive's spot at News Corp's British satellite TV subsidiary BSkyB.

Critics alleged that the hiring process was designed to close the door to other possible candidates, despite News Corp owning barely more than a third of BSkyB's shares.

Pastures new

In any case, for the moment Lachlan - until now generally seen as the heir presumptive - appears to have ruled himself out of the race.

Is the way clear now for James Murdoch?

Of Rupert Murdoch's three children from his second marriage, Lachlan was the first to join the board of the family firm when he became executive director in 1996, having earlier worked at Murdoch papers and TV stations in Australia.

Although he is to remain on News Corp's board, he is planning to move to Australia with his family, and may go into business on his own.

If that proves to be the case, he would be following in the footsteps of his sister Elisabeth, the first of the Murdoch younger generation to move out from the News Corp shadow.

At 37 the oldest of the three, she had already owned two TV companies in the early 1990s with her first husband, before joining BSkyB in 1995.