Britain is offering to help Nigeria crack down on violence in the troubled Niger Delta, which he said has disrupted oil supplies from the African nation, Prime Minister Gordon Brown said Monday.

Speaking ahead of talks in London with Nigerian President Umaru Yar'Adua, he said that up to 1.5 million barrels of oil a day were lost due to lawlessness in the Delta region.

He did not specify what kind of help Britain could provide, but said: "These are criminal acts ... What we're looking at is how we can help ensure there is law and order in what is a very dangerous area."

The Niger Delta, hub of Nigeria's multi-billion-dollar oil and gas industry but a deprived region, has been the scene of a low-level insurgency and criminal activity including kidnapping of oil workers and oil theft for many years.

The Delta "is an important strategic area for the world where oil supplies, if put at risk, create an instability if not a loss of supply to the world," Brown said ahead of the Nigerian president's visit to London.

"I'll be talking through with him some of the things that we could do, and perhaps the rest of the international community can do, to help," he told reporters at a monthly press conference in his Downing Street residence.

Unrest in the Delta has reduced Nigeria's oil output by a quarter, causing it to lose its position as Africa's biggest oil producer to Angola, according to April figures from the Organisation of Petroleum Exporting Countries (OPEC).

Several foreign firms, including French tyre company Michelin and oil servicing firm Wilbros, have left the Delta because of security problems.

Brown, speaking last week after returning from the Group of Eight (G8) meeting in Japan, said the world had to work to safeguard oil supplies, at the same time as developing alternative energy sources.

"We are working with the Iraqi government to build capacity in the oil sector there, and we are discussing with the Gulf states and others how sovereign wealth funds and oil revenues can be recycled into wider energy investments," he told the House of Commons last Thursday.