UK troops launch Operation Tor Shezada in Afghanistan
Hundreds of British soldiers have launched an operation against Taliban insurgents in Afghanistan.
Operation Tor Shezada began early on Friday morning in Helmand province in the south of the country.
Soldiers from the 1st Battalion The Duke of Lancaster's Regiment are trying to clear the Taliban from an important stronghold in the Nad Ali district.
The Brigade Reconnaissance Force (BRF) was among the first wave of troops.
Under cover of darkness, this small elite unit launched an airborne assault deep into insurgent-held territory.
Operation Tor Shezada, which means black prince, is a mission to seize a Taliban-controlled town in central Helmand and try to restore government rule.
Hundreds of British and Afghan forces are moving by land and air towards the town of Saidabad.
It is one of the areas that UK forces were unable to clear during Operation Moshtarak earlier this year.
As many as 180 insurgents are believed to use the town as a base; it is where bombs are made, attacks are planned and injured fighters are treated.
The area is seeded with IEDs, the home-made bombs that have killed and maimed so many soldiers and civilians.
When troops have entered the area in the past they have encountered stiff resistance.
In the words of the commanding officer, Lt Col Frazer Lawrence, they will try to "steal" Saidabad but are "prepared to fight for it".
Maj Marcus Mudd, the commander of the BRF, said his troops would be dropping in behind enemy lines.
In an eve-of-battle address, he urged his men to move quickly to win over the local population with the message that the Nato-led International Security Assistance Force (Isaf) would be here to stay.
Radio broadcasts have been used to warn people that this operation is taking place, although it is unclear how many will have been able to hear the message.
There are two ways of viewing Operation Tor Shezada.
On the positive side, the area now being 'cleared' of Taliban is said to be the last remaining centre of population in the Nad Ali area not yet under Afghan government control. This is a joint operation with the Afghan army, a continuation of the largely successful process of British troops mentoring and partnering their Afghan allies.
But on the negative side one might well ask why, if Nad Ali has been officially such a success, do hundreds of British and Afghan soldiers need to risk their lives going in to clear an area (Saidabad) that we had never heard of but is apparently a hotbed of Taliban insurgents?
The truth is that clearing central Helmand of insurgents, then bringing in elements of government that the local population can actually trust, is taking rather longer than commanders had hoped.
The Taliban have certainly lost a safe haven there this year, but they have not gone away. They are lurking in the background, intimidating locals not to co-operate with Nato and the Afghan government, and waiting for the day when foreign forces pull out. And they believe they can sweep aside government forces and reassert control.
Operation Tor Shehzade may well achieve short-term tactical success. The challenge will be to see if it delivers lasting security.
It is a mark of how controversial the issue of civilian casualties is that Maj Mudd cautioned his men to show restraint, telling them "if we fail to protect the population, we will fail in our mission".
Until a few years ago, Nad Ali was a relatively peaceful district in the central Helmand river valley.
But the combination of a corrupt and brutal police force and an abusive local government, together with an aggressive poppy eradication programme, turned it into a virulent insurgent stronghold.
Local farmers, with encouragement and support from the Taliban, took up arms, creating additional strain on Britain's already overstretched troops.
Operation Black Prince is just the latest in a series of missions over the last year-and-a-half that have attempted to "clear" the insurgents from the district.
There has been progress.
Most of the towns and villages here are no longer under the complete control of the Taliban. The media and politicians are regularly flown in to witness what the military see as a success story.
But the veneer of normality is dangerously thin.
The Taliban have always been able to exert influence far beyond their numerical strength.
It is true that intimidation is the weapon of choice when it comes to coercing the local population, but there is also genuine support for insurgents who are largely drawn from the area.
Shopkeepers in the district centre complain that security is not good.
They insist that the Taliban still operate just 2km away and they fear being caught up in the fighting.
Motorcycle mechanic Sultan Mohammed wants the government to talk to the Taliban.
"You cannot bring peace by fighting - war is not the answer," he told me.
A large crowd gathered to listen in, nodding in agreement.
When asked whom they would like to see in charge in Nad Ali - the government, army, foreign forces or the insurgents - they all agreed that they wanted the Taliban.
In a rare insight into the insurgency they insisted that people do not join the Taliban for the money.
This contradicts Isaf's categorisation of the bulk of fighters as "$10 Taliban", who are susceptible to inducements to switch to the government side.
Instead, the men told me that the Taliban are people motivated by religion, anger at corrupt police and local officials and affront at the presence of foreign, non-Muslim soldiers in their midst.
Yet the military insists Nad Ali is a model of progress.
Lt Col Fraser Lawrence says Operation Moshtarak, which took place here and in neighbouring Marjah earlier this year, was "a huge success".
But attacks and casualties have continued to mount in both areas.
The US Marine Corps to the South West of here is struggling with a resurgent Taliban.
A combination of influence and intimidation means that progress has been far slower than first predicted by military commanders.
Operation Tor Shezada is only possible because extra British forces have been brought in to Afghanistan.
The transfer of other troops from areas like Sangin will also increase their ability to tackle the insurgency later this year.
But the challenge in Helmand is, and always has been, to win over the local population.
As British troops embark on another bloody summer in Afghanistan, it is a battle they have yet to win.