A Libyan envoy¹ representing Col Muammar Gaddafi has been in London in the past few days for talks with British officials, the BBC has learnt.

BBC获悉，在过去的几天中，一位利比亚特使代表卡扎菲在伦敦与英国官员进行会谈。

Mohammed Ismail was a senior aide to Col Gaddafi's son, Saif al-Islam
Mohammed Ismail, an aide to one of Col Gaddafi's sons, was apparently² told the Libyan leader had to give up power.

The Foreign Office said "in any contact that we do have we make it clear that Gaddafi has to go".

Meanwhile, the US says air attacks have destroyed about a quarter of the Libyan government's military's capabilities³.

Following the defection（背叛，缺点） on Wednesday of the Libyan Foreign Minister, Moussa Koussa, there were unconfirmed reports that other senior Libyans were defecting.

Al-Jazeera said the intelligence minister, deputy foreign minister and General People's Congress speaker were awaiting flights in Tunisia.

Oil Minister Shukri Ghanim has denied any intention to leave Libya. Ali Abdul Salaam⁴ Treki, who was recently named as Libya's permanent representative to the United Nations, is not accepting the post.

A government spokesman told reporters that they were all in Libya, but that it was also possible that some had left the country on a mission.

Koussa debriefed⁶

BBC diplomatic correspondent James Robbins understands that Mr Ismail - a senior aide to Saif al-Islam Gaddafi - visited London in recent days.

The Foreign Office refused to confirm the visit, saying it was "not going to provide a running commentary on our contacts with Libyan officials, but that in any contact that we do have we make it clear that Gaddafi has to go".

It seems that the envoy may have wanted to explore a possible exit strategy for the Libyan leader, but the Foreign Office insist their policy is to encourage all those around him to abandon what they call "a brutal⁷ regime" and embrace a better future for Libya, our correspondent says.

It is not clear on whose authority within the regime Mr Ismail was in London, but he is thought to have returned to the Libyan capital, Tripoli, he adds.

There has been mounting speculation⁸ that Col Gaddafi's sons, particularly Saif al-Islam, Saadi and Mutassim, are willing to discuss exit strategies, either for the whole family or only the Libyan leader.

The reports of Mr Ismail's visit come as British diplomats⁹ and intelligence officials continue to debrief⁵（盘问） Moussa Koussa, Libya's foreign minister and former long-time head of its external intelligence service.

UK Prime Minister David Cameron said Mr Koussa's defection told "a compelling story of the desperation and the fear at the very top of the crumbling¹⁰ and rotten Gaddafi regime".

He also insisted that Mr Koussa had not been offered immunity¹¹ from prosecution¹². Scottish prosecutors¹³ have asked to interview him about the 1988 Lockerbie bombing, which left 270 people dead, though government sources told the Guardian¹⁴ they did not think he was involved.