* PM criticised for saying troops have accomplished mission
* Words echo banner used for Bush's 2003 Iraq war speech
* Concerns over security, drugs, rights in Afghanistan
By Peter Griffiths
LONDON, Dec 16 (Reuters) - Prime Minister David Cameron said on Monday that British troops could leave Afghanistan next year with a sense of having accomplished their mission, despite worries about the ongoing Taliban insurgency, drug cultivation and human rights abuses.
British media compared his comments to a banner bearing the words "Mission Accomplished" that was strung across the bridge of an American aircraft carrier in 2003 for a speech about the Iraq war by former U.S. president George W. Bush.
The message came to be seen by the president's critics as hubristic, premature and triumphalist - it was followed by another decade of fighting in which tens of thousands of people died across Iraq.
During a pre-Christmas visit to British soldiers in southern Afghanistan, Cameron was asked if they would be able to return home with the message "mission accomplished" after 12 years of fighting. He replied: "Yes, I think they do."
"The absolute driving part of the mission is a basic level of security so it doesn't become a haven for terror," Cameron added. "That is the mission, that was the mission and I think we will have accomplished that mission."
Cameron's critics said the words were misguided, given the widespread concerns over Afghan security, the drugs trade, human rights and allegations of corruption under the governance of President Hamid Karzai.
Afghanistan, which is preparing for elections next year, still faces a potent Taliban insurgency as the United States and other foreign powers withdraw their troops.
Yury Fedotov, head of the U.N. Office on Drugs and Crime, said in October that Afghanistan risks becoming a "full-fledged narco-state". Earlier this month, a U.N. report criticised the slow and uneven implementation of a law designed to protect women from violence.
Opposition Labour lawmaker Paul Flynn, a prominent critic of the Afghan war, attacked Cameron, highlighting the number of British soldiers killed or injured and the financial costs.
"Mission Accomplished': 446 dead, 2,000 grievously injured, uncounted Afghan dead, 40 billion pounds UK cost, crook Karzai rules, drugs rampant," he said on Twitter.
Labour's defence spokesman Vernon Coaker MP said it was too soon to suggest the Afghan mission was over when British soldiers are still fighting the Taliban. "The job is not done in Afghanistan," he added.
Visitors to social media sites drew comparisons between Cameron's words and the Bush event in 2003 and said the British leader may come to regret his comments.
"We are leaving before the job is complete. Our troops are superb but our politicians have let them down," wrote Twitter user Norman Phillips.
Britain still has about 5,000 British troops in the country, but plans to withdraw them by the end of next year.
Asked if the prime minister regretted using words, Cameron's spokesman told reporters: "No, of course not."
"He was explaining what our armed forces have achieved. Is the situation in Afghanistan a perfect one? As the prime minister himself has said, no. But has the situation improved significantly in terms of the threat that terrorists pose, and that was the reason we intervened, yes it has." (Editing by Andrew Osborn and Andrew Heavens)