By Frank Gardner
Security correspondent, BBC News
Capt Ben Babington-Browne is one of seven soldiers to die in the last week
Defence Secretary Bob Ainsworth has given his first major speech in the job. He said Britain's safe future was dependent on achieving success in Afghanistan - but that would not come without a price in lives lost.
There were no huge surprises in Bob Ainsworth's speech. He has been an understudy for this job for some time, working under John Hutton and has long been immersed in the whole issue of Afghanistan.
Broadly speaking, it was a sober, fairly gloomy and quite realistic speech.
Put simply, Britain is going to take more casualties in Afghanistan and we're going to be there for some time.
The military put these things in terms of operations. Herrick is the codename for Afghanistan - Telic was the codename for Iraq.
Britain is currently on Herrick 10 and every six months that number goes up. They are currently planning for Herrick 15 and there are probably plans for further ahead than that, certainly as far as 2012.
The intention then is to keep thousands of British troops there for a very long time - or at least the foreseeable future - until Afghanistan is stabilised. And that's not going to happen quickly.
Mr Ainsworth - and John Hutton before him - have tried to set out clearly why Britain is in Afghanistan in the first place.
But there is a credibility gap here. Most of the country doesn't really understand why we are there.
Indeed, there are holes in the government's argument too. If we are trying to stop al-Qaeda building bases from which to attack us - well, al-Qaeda doesn't have proper bases in Afghanistan.
Their bases are on the Pakistani side of the border.
The idea that if you have forces in Afghanistan it will stop al-Qaeda attacking Britain doesn't completely hold water because ministers have said themselves that 75% of the terror plots in this country are linked back to Pakistan.
Really, it would be more accurate to say Nato is trying to keep al-Qaeda out of Afghanistan, while admitting that it has successfully transplanted itself elsewhere.
Moreover, the very fact that there are Western troops in Afghanistan is an incentive, a recruiting agent, for al-Qaeda and other jihadist groups to go and fight the West and drive them out.
It is certainly quite a complicated jigsaw.
The priority for Britain and other international troops is to stabilise Afghanistan and to improve people's standard of living.
But it's not just about military success; it's about improving governance too.
Afghanistan is in many provinces quite badly governed with very corrupt policemen who are taking bribes and extorting money from people.
To look at the big picture, Nato and the Brits think they can win pretty much every tactical engagement that they encounter the Taliban in.
Bob Ainsworth said success in Afghanistan would be hard-won
Sometimes with difficulty - because they are a very tenacious enemy - but with superior weaponry, training, air support and so on the Taliban can be beaten on the ground.
Crucially though, that victory is only at a tactical level.
The bigger picture is that fighting is only a small part of the problem in Afghanistan. One of the major problems is bad governance.
Ordinary Afghans are having to decide if life is better in areas contested by Nato or in areas controlled by the Taliban, where they might have to live under draconian rules but at least things are stable.