David Cameron was given a red-carpet welcome as he arrived in the US today for talks with President Barack Obama which are expected to focus on the timetable for withdrawal of international troops from Afghanistan.
A guard of honour greeted the Prime Minister and his wife Samantha as they touched down at Andrews Air Force Base, near Washington, to the sound of a military band playing the national anthems of both countries.
Central to Mr Cameron's three-day visit are top-level discussions on the timing of the handover of lead security responsibilities in Afghanistan to home-grown forces during the course of 2013, allowing the vast bulk of British and American troops to return home by the end of 2014.
But it is also being seen as an opportunity to build on what the two leaders have termed the "essential relationship" between the UK and the US.
And the first item on Mr Cameron's schedule is an introduction to the President's favourite sport of basketball, with a visit to a university game in Ohio.
After meeting Mr Obama in the White House this evening, Mr Cameron will join the President on Air Force One to fly to the University of Dayton, where they will watch the first match of the popular College March Madness tournament, which is televised to big audiences across the US.
Mr and Mrs Cameron were greeted at Andrews by the US chief of protocol Ambassador Capricia Marshall, as well as the UK ambassador in Washington Sir Peter Westmacott, the American ambassador to London Louis Susman and a welcoming party of senior officials from the US National Security Council and State Department.
They were travelling to Blair House, the official US state guest house in Washington, to be greeted by assistant chief of protocol Randy Bumgardner.
After the Prime Minister leaves for the White House, Mrs Cameron was joining first lady Michelle Obama to visit Washington's American University, where they will talk to children who have been taking part in a mini-Olympics event. They will later say hello to girls from Elizabeth Garrett school in north London who first met Mrs Obama during her trip to the UK in 2009 and have been invited over by the first lady for a return visit.
Mr Cameron and Mr Obama used a joint article in today's Washington Post to vow to maintain the trans-Atlantic special relationship which has endured since Churchill and Eisenhower were allies in the Second World War.
In the wake of the recent deaths of six British soldiers and the massacre of 16 Afghan civilians by a renegade US serviceman, they acknowledged that Nato-led operations in Afghanistan remain "a difficult mission".
But both men indicated they would not be knocked off course or pushed into a precipitate exit from Afghanistan, saying: "We honour the profound sacrifices of our forces and in their name we'll carry on the mission."
Their talks at the White House tomorrow will focus on the question of when home-grown Afghan forces will be ready to take over lead responsibility for security in the whole of the country, as they already have done in some provinces.
They will set the scene for the Nato summit in Chicago in May, when a date for transition to lead Afghan control is expected to be announced. Nato agreed at an earlier summit in 2010 that transition should come before the end of 2013, but there was speculation today that the date may be brought forward to the summer of next year.
International troops would remain in support roles - including combat support - until the end of 2014, but the move to an Afghan lead would pave the way for British and American troops to start coming home in large numbers. At present, some 33,000 US personnel and 500 Britons are due to be withdrawn over the course of 2012 and no announcements of further drawdowns are expected this year.
Mr Cameron wants to use this week's talks to ensure that the US and UK are "in lockstep" over the handling of the sensitive conclusion to an operation which will have lasted 13 years by the time the last international troops are pulled out.
The two leaders said in today's article they were "proud of the progress our troops have made in dismantling al Qaida, breaking the Taliban's momentum and training Afghan forces".
They added: "Our troops and citizens have long shown what can be achieved when British and Americans work together, hand and heart, and why this remains an essential relationship - to our nations and to the world.
"So, like generations before us, we're going to keep it up. Because with confidence in our cause and faith in each other, we still believe that there is hardly anything we cannot do."
The unrest in Syria, Iran's nuclear ambitions and the fragile world economy will also be on the agenda for tomorrow's meeting, which will be followed by a star-studded state dinner at the White House.
Shadow chancellor Ed Balls said: "If David Cameron and George Osborne are going to spend the week before the Budget in America, they should use the trip to ask President Obama for some economic advice.
"While Britain's economy has stalled and unemployment has reached a 17-year high, the US economy is strengthening and the jobless rate has come down to a three-year low.
"The US government's more balanced and steady approach to deficit reduction up to now means they have more than recovered all the output lost in the global recession, while in Britain we are still almost 4% below our pre-crisis peak."