The UK presence in Afghanistan will need to go on for decades to help rebuild the country, British ambassador Sir Sherard Cowper-Coles has said.

"The task of standing up a government of Afghanistan that is sustainable is going to take a very long time," he told BBC Radio 4's Today programme.

He added that the Afghan people wanted the UK presence to help resist the Taleban and develop the country.

Extra diplomatic staff are being deployed to Afghanistan this year.

"The message we are getting, the message I had only last week down in Helmand from the people of the villages there, was, 'Please protect us from the Taleban,'" said Sir Sherard.

"Their worry isn't about us staying, it's about us going; about us not finishing the job of standing up the police, standing up the security forces, standing up the judicial system, putting schools and hospitals in place."

He added: "They remember the Taleban - they have had a test-drive of Taleban rule and if there is one thing they are clear about it's that they do not want to return to the dark days of medieval Taleban rule."

'Huge commitment'

The British government planned to send as many as 35 extra diplomatic staff to Afghanistan.

The priorities would be to combat corruption, help build government institutions in the south and to tackle the production of opium, the Foreign Office said.

The UK troop numbers in Afghanistan are also being boosted to about 7,700 this year, mainly based in the volatile Helmand province, where they have been fighting the Taleban.

BBC world affairs editor John Simpson said the British embassy in Kabul was likely to become the UK's biggest anywhere.

"It's a huge commitment," he said.

"The fact that Sir Sherard is here as ambassador is itself a sign of the Foreign Office's determination to upgrade its whole representation in Afghanistan.

"He's a big hitter in the diplomatic service."

BBC world affairs editor added: "There is real concern in the Foreign Office in London that the new government of Gordon Brown will take a short-term view of Afghanistan, rather than the long-term view that the Foreign Office thinks is needed."

Sir Sherard said: "We are going to win this, but it's going to take time.

"It's a marathon rather than a sprint - we should be thinking in terms of decades."

PHOTO CAPTION

A British soldier in Afghanistan opium field