Foreign Secretary William Hague has welcomed the high turnout for presidential elections in Afghanistan, taking place just months before the withdrawal of international troops.
Millions of Afghans queued to cast their ballots despite threats of violence from Taliban militants. Turnout was so high that some polling stations ran out of ballot papers.
With President Hamid Karzai constitutionally barred from standing for a third time after 13 years in office, the election promises to deliver the first democratic transfer of power in Afghanistan's history.
Mr Hague said: "This is an historic moment for Afghanistan and its people. Across the country, millions of Afghans have been voting for a new president. It is a great achievement for the Afghan people that so many voters, men and women, young and old, have turned out in such large numbers, despite threats of violence, to have their say in the country's future.
"Now that all the votes have been cast, I hope all parties will show patience and respect while the electoral authorities go to work to count and check the ballots, and declare the results."
Eight candidates ran in the presidential elections, including three women running as second vice presidents. Front-runners to replace Mr Karzai - the only president since the overthrow of the Taliban regime in 2001 - are former foreign ministers Abdullah Abdullah and Zalmai Rassoul, and former finance minister Ashraf Ghani Ahmadzai.
Polls suggest that no candidate is likely to secure more than 50% of the vote when preliminary results are announced by the Independent Election Commission on April 24, which would trigger a second-round run-off on May 28.
Voters were also casting their ballots for members of Afghanistan's provincial councils.