Gordon Brown is expected to invite two controversial world leaders, Colonel Muammar Gaddafi of Libya and Hugo Chavez, President of Venezuela, to an international oil summit in London.

The invitation could bring the Libyan leader to Britain on his first official visit after years of isolation. An invitation could also bring Mr Chavez, the champion of socialist revolution in South America, to London and an unlikely photo-opportunity with Mr Brown.

Drawing up the guest list for the Prime Minister’s promised summit in December, a follow-up to the international meeting of oil producers and consumers in Saudi Arabia over the summer, was always likely to be an awkward business.

Mr Brown is keen to be seen to be addressing the issue of rising fuel prices, and to be acting to coordinate an international response to rising demand.

However, for all the possibilities that oil diplomacy might yield, it was likely that news of who was coming would overshadow the agenda.

The head of at least one key oil-producing nation, President Mahmoud Ahmadinejad of Iran, was unlikely to be considered a suitable guest, following anger over his perceived nuclear ambitions.

Meanwhile the arrival of Colonel Gadaffi in the capital would be certain to draw headlines. It is over two decades since British diplomatic relations with the country were severed, after shots fired from the Libyan embassy killed WPC Yvonne Fletcher, who was policing demonstrators outside.

Relations froze further after the bombing of an American airliner over Scotland in 1988. Since then the Libyan Government has accepted responsibility for the bombing, and ‘general responsibility’ for the killing of WPC Fletcher, and Tony Blair visited the country to meet the Libyan leader last year.

Colonel Gadaffi travels with female bodyguards and in recent trips to Europe, he has kept to his preference of staying in a black Bedouin tent, pitching it in government owned gardens in Paris and Brussels.

The arrival of the flamboyant President Chavez would also be likely to cause a stir. He would be coming to discuss oil supply in a city which recently cancelled his supply of oil to its fleet of buses. The deal, struck by former mayor Ken Livingstone, was recently cancelled by Mr Livingstone's successor Boris Johnson.

Informal invitations have reportedly been extended to both leaders, though formal invitations have not yet been sent out.

There are also fears that it could be difficult to attract high profile guests to the summit. The previous international oil summit, in Jeddah, in June, was judged to have been unproductive. At December’s summit, as well as the difficulty of finding an appropriate representative for Iran, there may be some trouble in finding an appropriate representative for America. The summit will fall after the US elections but before the new president has been sworn in.

A spokesman for Downing Street said: “The Prime Minister is determined to act domestically and to work with others internationally to address the functioning of the international oil markets.”

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