Signs that Libyan leader Muammar Gaddafi is reining in his liberal-leaning son Saif al-Islam could weaken already fragile prospects for democratic and free-market reforms in the North African country.

Libya's relations with the West took a leap forward in 2003 when it gave up banned weapons programmes and again last year when it agreed with the United States to settle compensation claims for attacks including the 1988 Lockerbie airliner bombing.

Saif al-Islam, 36, took a central role in negotiations to end years of sanctions that had left OPEC member Libya out of bounds for most foreign investors. He has also called for more media freedom and deeper democracy.

But last week the government took control of an independent television channel linked to Saif al-Islam, stoking speculation he had pushed the reform agenda too far and angered powerful state apparatchiks who favour the status quo.

"The way he (Saif al-Islam) is doing it is provocative and he is incurring his own father's anger," said Ashur Shamis, an analyst and prominent London-based Libyan exile. "He is disrupting lots of other groups in the country."

Questions were already being asked about the influence of Saif al-Islam - once identified by some observers as his father's most likely successor - after he announced in August he was withdrawing from a political role.

As his fortunes seem to wane, Libya watchers point to the rising profile of his younger brother, Mutassim.

Where Saif al-Islam challenged the established order, Mutassim has quietly built the support of powerful establishment figures by appealing to their conservative instincts.

Little is known of Mutassim besides a military background and a low profile that contrasts with his outspoken, globe-trotting brother, an English speaker with a master's degree in business administration.

The publicity-shy Mutassim broke with tradition on April 21 when he made an official visit to the United States as Libya's national security adviser and met Secretary of State Hillary Clinton in Washington.

Eurasia Group Middle East and North Africa director Geoff Porter said in a note that while Saif al-Islam was "jet-setting and modelling for the cover of GQ (magazine)", Mutassim was building domestic alliances that had positioned him to take over from his father.

Mr Porter said that has implications for foreign investors, whose ability to operate in Libya depends on close ties to parts of the Gaddafi clan.

Firms that had closely allied themselves with Saif al-Islam "may find themselves at a disadvantage in coming months as (his) star continues to fall", he said.

But the idea that big foreign investors need a powerful Saif al-Islam in order to gain access to Libya is exaggerated because it is his father who is the ultimate decision-maker, said Jane's Middle East editor David Hartwell.

"I don't see a threat per se to Western investment, because the opening to the West is a Gaddafi policy," said Mr Hartwell.

His view was echoed by other analysts. Most said the shift in power would not harm the prospects for Western firms such as BP and ExxonMobil, which have capitalised on Libya's decision to open up by investing millions of dollars in energy projects there.

Col. Gaddafi, who holds no official state position, is keeping the world guessing over who might succeed him as Brother Leader and Guide of the Revolution, if indeed the title survives him.

At around 66, he is a relative youngster compared to other veteran African leaders.

"It may be premature to put too much effort into speculating on which people might succeed to various parts of his multi-faceted legacy," said David Mack, a Middle East Institute scholar and former US diplomat.

In the meantime, foreign governments and investors know that the benefits of doing business outweigh the risks from a volatile political scene and a murky business climate. US-Libyan trade tripled to $4.9 billion last year from $1.67 billion in 2005. "Is the lack of process and the continued unpredictability over the leadership succession something the US government is comfortable with?" said James Ketterer, an international relations expert at the State University of New York.

"It seems that, for now, there's a trade-off that the US is willing to make and it's not going to press hard on issues of democracy."