Gordon Brown has scaled down his meeting in London with leaders of the major oil-producing and consuming countries.

Reports said that the downgrading of the summit to ministerial level followed a threatened boycott from Opec unless heads of state like Libya's Muammar Gaddafi, Mahmoud Ahmadinejad of Iran and Venezuela's Hugo Chavez were invited.

But the Prime Minister's spokesman said that the decision was taken to make the December gathering into a less high-profile meeting of energy ministers because heads of state and government will have a chance to discuss oil issues at US President George W Bush's global summit in Washington on November 15.

Mr Brown announced plans for a conference of heads of state to discuss fuel policy when he attended a meeting held in the Saudi Arabian city of Jeddah in June, at which oil producers and major consuming countries discussed how to respond to the spike in prices.

Crude was then selling for around $140 a barrel, sparking demands from consumer nations for Opec to increase supplies to ease price pressure at the petrol pump.

But slackening of demand has since led to a precipitous fall to around $65-a-barrel, leading Opec last week to announce a 1.5 million barrel-a-day cut in production.

Opec secretary general Abdullah al-Badri said: "The meeting (in Jeddah) was called because prices went out of control but, in my opinion, there should be no follow-up."

Mr al-Badri was quoted as saying that the cartel had threatened to boycott the event unless an invitation was extended to the heads of all 13 of its Opec member countries. He said that some leaders had not received invitations, but did not name which.

However, Downing Street said: "Given the fact that there will be a world leaders' meeting anyway on November 15 to discuss the international economic situation and no doubt oil will be discussed as part of that, we decided to revert to the form of approach taken at the Jeddah meeting, which was that this should be a meeting primarily of energy ministers."

The Department of Energy and Climate Change confirmed that Energy Secretary Ed Miliband will now chair the summit of 38 nations in London on December 19.

© Independent Television News Limited 2009. All rights reserved.