British Prime Minister David Cameron was today to urge Barack Obama to back a concerted attempt to end the stalemate in Libya over the next few weeks.

At one-to-one talks in Downing Street, the Prime Minister and US President are expected to agree to press other Nato countries to shoulder more of the burden of the military effort to drive Colonel Gaddafi from power.

Although the President wants Britain and France to remain in the lead, British ministers denied that Mr Cameron would demand that America do more towards the air campaign. "It's a myth that the US is doing nothing," one British source said. "This is about ensuring that we don't lose momentum in Libya."

While any differences over America's role are likely to be kept private, Libya is expected to top the agenda in today's bilateral talks. Mr Cameron and Mr Obama will then be joined by their security advisers to discuss plans for closer co-operation through a joint national security taskforce. Later the President will address MPs and peers in Parliament's Westminster Hall.

Also on the leaders' agenda will be the Arab Spring; Afghanistan and Pakistan following the killing of Osama bin Laden; the deadlocked Middle East peace process; and the global economy.

Although both men share a determination to hand control of security in Afghanistan to Afghan forces by 2015, there is some concern in Washington that Mr Cameron jumped the gun last week by announcing plans to bring home 400 British troops this year.

Last night Mr Obama discussed the economy, Libya, Afghanistan and climate change during a 40-minute meeting with Ed Miliband, which Labour described as "warm and friendly".

Libya will also be high on the agenda at a two-day G8 summit starting tomorrow in the French resort of Deauville. British sources predicted that the discussions on the Libyan crisis and implications of the Arab Spring, which has seen regimes toppled by popular uprisings in Egypt and Tunisia, to be "pretty frank".

Two G8 members, Russia and Germany, abstained in the vote on the UN resolution authorising military action.

Mr Cameron, President Obama, the French President, Nicolas Sarkozy, and Stephen Harper, the Canadian Prime Minister, will discuss the military action in the margins of the summit.

Concern over the apparent impasse surfaced in the Commons yesterday after it emerged that Britain is ready to deploy helicopter gunships to Libya.

Nick Harvey, the Armed Forces minister, was forced to deny accusations of "mission creep" with British and French forces widening their military effort. He disclosed that the Government is considering paying an "operational allowance" to servicemen and women involved in Libyan missions - a sign that ministers could be preparing for a lengthy commitment.

- THE INDEPENDENT

By Nigel Morris, Andrew Grice