By Paul Reynolds BBC world affairs correspondent

Call him what you will - maverick, hero, desert recluse, mercurial, state terrorist - Libyan leader Muammar Gaddafi is a survivor.

With a visit from British Foreign Office Minister Mike O'Brien, the first visit by a British Government minister in 20 years, he has been cleaned up, repackaged and is ready for the outside world again.

The British line is that it is better to engage Libya in the fight against al-Qaeda and international terrorism than to go on isolating it.

Just what help he can give is not all clear, though. British Foreign Office officials murmur about "intelligence".

They also say that Libya has agreed to sign an international protocol on chemical weapons which would enable inspections to take place of Libyan installations suspected of developing the means to make them.

The Libyan leader is being pressed to take responsibility for Lockerbie

How different from Saddam Hussein.

The Iraqi leader can do no good and is slotted for American action, of a type to be determined but likely to be unpleasant.

Colonel Gaddafi is blamed for one of the worst acts of terrorism in the modern world and yet is still in power and looks set to continue his individualistic rule which started in 1969 when he led a coup against King Idris.

More than that, he is being brought back into the international mainstream.

Recently he played a leading role in the establishment of the African Union, which took over from the old and discredited Organisation of African Unity.

He has managed his rehabilitation because, following the Lockerbie bomb, the United States and Britain chose the route of international justice not military revenge.

Unlike Col Gaddafi, Saddam Hussein can apparently do no good

Unlike the belligerent Saddam Hussein, Colonel Gaddafi made enough concessions to make negotiation with him worthwhile.

He agreed to pay compensation for the death of London policewoman Yvonne Fletcher, who was shot dead outside the Libyan embassy in 1983.

He handed over his agents for trial for the Lockerbie explosion. One of them was convicted.

He renounced "international terrorism", though the Americans accuse him of maintaining links to Palestinian groups classed by them as terrorist.

Sanctions suspended

Those moves led to the suspension of UN sanctions against Libya imposed after Lockerbie. Flights and trade, especially in the oil industry, resumed.

Libya has already paid compensation for the death of PC Yvonne Fletcher

But the sanctions will not be formally ended until Gaddafi moves on two further demands -- compensation for the Lockerbie families and accepting responsibility for the actions of the agent convicted of planting the bomb.

Despite reports in May that he had made an offer to the families of $10m each, nothing has yet been agreed.

The Americans also maintain their own sanctions as they are less convinced that this leopard has changed its spots. Libya remains on Washington's list of states "sponsoring terrorism".

Washington will be watching closely to see if the British efforts to engage Gaddafi bear further fruit.