Libya’s government said yesterday it is ready to negotiate reforms but only provided Muammar Gaddafi is not forced out, as loyalists troops pushed rebel fighters back from the key oil port of Brega.

Nato-led air strikes have destroyed 30 per cent of the regime’s military capacity since the UN-backed bombing campaign started on March 19, an alliance commander said, even as the rebels suffered their first significant loss of territory in almost a week.

A one-million-barrel supertanker docked in the rebel-held port of Tobruk to pick up the first oil cargo for 18 days, the specialist shipping newsletter Lloyd’s List said, in a big boost to the anti-Gaddafi forces’ finances.

Government spokesman Mussa Ibrahim told journalists in Tripoli that everything except the departure of Col Gaddafi was negotiable, saying he was a unifying figure after ruling the nation for four decades.

“What kind of political system is implemented in the country? This is negotiable, we can talk about it,” Mr Ibrahim said. “We can have anything, elections, referendums.”

But Col Gaddafi’s future was sacrosanct, he stressed, only hours after the rebels flatly rejected a reported peace deal that could see the embattled leader’s son take charge of the North African nation.

The “guide of the revolution”, who has always rejected the title of head of state, was “the safety valve” for the unity of the country’s tribes and people, Mr Ibrahim said. “We think he is very important to lead any transition to a democratic and transparent model.”

In a show of defiance, Col Gaddafi greeted supporters late on Monday in his first public appearance since March 22 at his Bab el-Aziziya residence in Tripoli, bombed by coalition forces two days earlier, state television said.

Col Gaddafi’s son Seif al-Islam meanwhile dismissed former foreign minister Mussa Kussa, who defected to the West last week, as just a “sick and old” man who had succumbed to the psychological pressures of war.

Long seen as the heir apparent to his father before the wave of protests shook the country, Seif al-Islam briefly showed up at a Tripoli hotel to record an interview with the BBC in which he made dismissive comments about Mr Kussa, once a pillar of the regime.

The son, who had not been seen in public since coalition air strikes began on March 19, said Mr Kussa had been allowed to go abroad for medical treatment.

“Regarding Mussa Kussa, he said: ‘I’m on a travel ban list and I’m sick and I have to go every three months to Cromwell Hospital, in London, if I can get permission. I want to go there,’ so... and we allow him to go to Djerba, in Tunisia, so there’s nothing against that,” the younger Gaddafi said.

He added: “We have been bombed for two weeks, imagine the psychological pressure and you are sick and old, so you resign. It’s a war.”

Asked what information Mr Kussa might provide the West, Seif al-Islam said: “He’s sick, he’s sick and old, of course, he would come out with funny stories.”

But he dismissed the idea Mr Kussa might have secrets to share, for instance on the extent of the involvement of the Libyan intelligence services, in which he was long a senior figure, in the December 1988 bombing of a US airliner over Lockerbie, Scotland, which killed 270 people.

“Like what? The British and Americans know about Lockerbie, there’s no secrets any more,” the son said.

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