Foreign Secretary Boris Johnson is hosting international talks with US Secretary of State John Kerry aimed at finding a way to break the political stalemate in Libya.
Libyan prime minister Fayez Serraj joins representatives from France, Italy, Saudi Arabia and the United Arab Emirates in London amid deepening international concern about the plight of his country.
Five years after rebels supported by Western air strikes overthrew the regime of Colonel Muammar Gaddafi, Mr Serraj's UN-backed government of national accord is still struggling to impose its authority outside the capital, Tripoli.
Government forces, supported by US warplanes, have been closing in on the key city of Sirte which was seized more than a year ago by Islamic State fighters who took advantage of the continuing chaos.
However much of the rest of the country is in the grip of faction-fighting by rival armed militias while the economy has been hit by the collapse of the oil exports which largely kept it afloat.
Diplomats gathered in London are also expected to hold talks in the margins of the main meeting to discuss the continuing crisis in Syria.
Speaking in Dublin on Sunday, Mr Kerry said that despite the bitter falling out between Washington and Moscow, it would be possible to resume peace talks in the coming months.
"We have a fundamental responsibility to try to push the process forward," he said.
"My hope is that over the course of the next two or two-and-a-half months we might be able to find a way to get to the table and begin some kind of legitimate and long overdue conversation."
Following the talks, Mr Kerry will join London mayor Sadiq Khan in a discussion with young people on current issues on current issues, including climate change and countering violent extremism.