Afghanistan will not be "a perfect democracy" by the time western troops return home, David Cameron admitted as he arrived in Washington for a three-day visit to the United States.
But he stressed the public was keen for an "endgame" to a military operation that has lasted more than a decade and cost hundreds of British lives. After receiving the red-carpet treatment when he arrived at Andrews Air Base last night, the Prime Minister joined President Barack Obama on board Air Force One to watch a university basketball match in Ohio.
The two leaders will hold talks in the White House today over the recent turbulence in Afghanistan, including a detailed discussion on the withdrawal of western troops from the country.
Last night Mr Cameron sought to play down expectations over the eventual prospects for Afghanistan. He said: "I think people want an endgame. They want to know that our troops are going to come home, they have been there a very long time."
The Prime Minister made clear his definition of a successful completion to Britain's mission is less ambitious than the dream of a modern democracy first envisaged when the Taliban was ousted from power in 2001.
He said: "What I define as doing the job is leaving Afghanistan looking after its own security, not being a haven for terror, without the involvement of foreign troops. That should be our goal, so that the British public, our troops and the Afghan Government frankly, know there's an end to this."
Speaking on board his chartered plane as he headed to the US, Mr Cameron added: "I accept it won't be a perfect democracy. There will be huge development problems."
Mr Cameron said he and Mr Obama will use their talks to ensure the UK and US are "absolutely in lock-step" over the withdrawal process, as well as to discuss future support for Afghanistan after the International Security and Assistance Force has left.
Mr Cameron also spoke of his horror over the brutal repression of protesters by Bashar al-Assad in Syria – another subject that will be central to his meeting with the President. "What is happening in Homs is completely appalling," he said.
The two leaders will look at what extra diplomatic and economic pressure can be brought to bear on Damascus to speed up Assad's removal from power, but are unlikely to consider more radical measures such as arming rebel groups or providing air cover of the kind seen in Libya last year. Mr Cameron said: "The shortest way of ending the violence is a transition where Assad goes, rather than a revolution from the bottom, transition at the top rather than revolution at the bottom."
Last night's visit to the basketball game between Mississippi Valley State University and Western Kentucky University is part of a packed programme designed to display the warmth of trans-atlantic relations, including a star-studded state dinner in the White House tonight.
Mr Cameron is the first foreign leader to be invited on board the President's personal plane and last night said he had no doubt of the continuing strength of the special relationship. "I think the special relationship survives. It's increasingly strong, based on common interests and common values."
Mr Cameron said he was "very glad I do get on so well with Barack Obama", adding: "Obama's approach is deeply rational and reasonable, and also very strong.
Special guest: The flight on Air Force One
The "special relationship" between the US and UK reached new heights last night as David Cameron became the first foreign leader to be invited to travel with President Obama on Air Force One.
During the 70-minute flight to Dayton in Ohio, to attend a basketball match, the Prime Minister is sure to have noticed the £200m Boeing VC-25A's retro interiors, reportedly selected by Nancy Reagan when the plane was commissioned in 1985. However, in terms of equipment, AF1 is state-of-the-art, complete with an inflight refuelling system, flares that can divert heat-seeking missiles, and a shield to protect it's electrics from the electromagnetic pulse of a nuclear blast.
Air Force One is the code name applied to any plane the President is travelling on, but the aircraft Mr Cameron will fly in is one of two which are mainly used as the President's "flying Oval Office". Within 4,000 sq ft of floor space, the plane boasts 87 phones, 19 televisions, a gym and a television studio. The plane's 26-strong crew can cater for 100 passengers, usually made up of the Presi- dent's staff and White House press.