The wild-eyed policemen were high on opium, harassing locals and demanding bribes from drivers on the road so recently built at the expense of the British taxpayer.

“I might as well shoot myself in the head,” said one officer, jaw slack and eyes unfocused, as he leant on his Kalashnikov. “We have no life, no salary, and no respect from the people.”

His tattered uniform flapping, he added, with apparent self-loathing: “It is true what people say: the police are the robbers round here.”

The scene illustrated the central problem facing the UK in Helmand province, where 8,000 British troops are trying to impose order. British counter-insurgency doctrine has a single, central objective: to deliver security to the people. Without this, the Taleban and the raft of other challenges cannot be met.

Since the arrival of British forces in 2006, however, security across the province has collapsed and British forces now face a swirling, toxic cocktail of Taleban infiltration, tribal feuding, banditry and drug-funded anarchy.

Among the most visible sources of criminal behaviour are the demoralised, underpaid and predatory Afghan police - and it is now the Taleban, with their reputation for brutal but impartial justice, who appear to be gaining ground in this war of popular perceptions, successfully presenting themselves as the guardians of the public.

Through the window of an estate agent, Maleeq Khan watched the antics of the police and sighed wearily. “This construction is pointless,” he said, gesturing at the road. “We just want security. If I rent a house to someone I can't even carry the money home without people killing me. The British are completely useless.”

The message was remarkably consistent across several dozen interviews The Times conducted on the city streets. Most also contrasted the local instability with the situation in the swaths of territory the Taleban hold.

In early September there was panic in Lashkar Gar when Marja and Nad Ali, two districts west of the city, fell to the Taleban after local police and militiamen allegedly abandoned their posts. It was the closest the Taleban had been to the Helmand capital and, as they moved openly around the outskirts, rumours swept Lashkar Gar that the city was about to fall.

An assault has yet to materialise, but in the weeks since stories have reached the city of a dramatic improvement in security in Nad Ali and Marja under Taleban rule. Two weeks ago the Friday bazaar in Marja was reopened, with the Taleban in control.

“When the Government was in charge, the police were beating people and stealing from them,” said Mr Khan. At the first bazaar under the new Taleban regime, there was no stealing by the Taleban and the only beating was of a man caught stealing a motorbike.

“The Taleban covered his face and clothes in the black oil,” said Mr Khan approvingly. “Then they paraded him through the bazaar. The children were throwing things at him and they made the thief stand on a platform and state his name, his father's name and his crime to the people. Then they beat him and threw him out. He won't do it again.”

Others in the city had similar tales. Many reported an apparent Taleban public relations drive which has seen such unpopular Taleban social edicts as bans on music, television, kite-flying and shaving of beards quietly dropped. There are also persistent reports of a Taleban amnesty for government officials and police who swap sides and a promise that the Taleban will defend poppy fields from government eradication.

“Support for the Taleban is up a lot,” said one man among a lounging group of shopkeepers. “They are completely different to how they used to be,” said another.

The Taleban have rebranded themselves, insisting that they should now be called Mujahidin (holy warriors) - a word that links them to the earlier Jihad against the Soviet forces.

At the British base in the city there is a belief that their forces are making gains on the battlefield, notably pushing back in Nad Ali and Marja, and that reconstruction efforts are starting to have a visible impact. There is also great hope in the new governor of Helmand, Gulab Mangal, who enjoys widespread approval as an honest and impartial public servant.

However, there is also frustration at the chronic weakness of Afghan government structures and a conviction that provincial powerbrokers and even figures in central Government are working to frustrate British efforts.

“The perception of the threat from the Taleban continues to outstrip the reality,” said the outgoing British commander in Helmand, Brigadier Mark Carleton-Smith. “This struggle is more down to the credibility of the Afghan Government rather than the threat of the Taleban.”

British and Afghan government figures accuse a cabal of former provincial officials, many of them figures sacked at British insistence because of their alleged links to the Helmand opium trade, of aiding the Taleban efforts. Their aim, apparently, is to create anarchy and present their own return to power as the only solution.

The accused include the former governor of Helmand, Sher Mohammad Akhundzada; the former police chief, Abdul Rahman Jan; and the latter's son, Wali Jan, an MP in the Afghan parliament.

They are blamed for the loss of Nad Ali and Marja to the Taleban. It was members of Abdul Rahman Jan's Noorzai tribal militia who occupied six key checkpoints that fell to the Taleban apparently without a fight.

“Since they were sacked, they have not let one governor, chief of police or government official do their job,” said one government official.

“The Taleban have been trying to get people to like them,” said a local reporter, who asked not to be named after a colleague was beheaded in June. “If we ask people: ‘Do you remember the old Taleban?', they say: ‘Yes - when they get the power again they will take out the stick again'.”

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