By Paul Adams
Diplomatic correspondent, BBC News
The Paras are deploying to Afghanistan after a break of just 18 months
When the head of the armed forces says we're not equipped to fight two wars, at a time when British forces are doing exactly that, we can be forgiven for wondering what's going on.
At a lunch with journalists on Tuesday, Air Chief Marshall Sir Jock Stirrup, the Chief of Defence Staff, warned that current operations had left the forces "stretched beyond the capabilities we have".
This sounded familiar enough, but he went on to describe in some detail the nature of the predicament.
"We are not structured or resourced to do two of these things on this scale on an enduring basis but we have been doing it on an enduring basis for years," he said.
Inevitably, this was translated into alarming headlines. "We can't fight two wars, says head of military," shouted the Daily Telegraph on its front page.
Is this what Sir Jock actually meant? The answer is yes and no.
Under current military planning assumptions, Britain's armed forces should be able to conduct one "enduring medium-scale operation" and one "enduring small-scale operation" at the same time.
This should be possible while sticking to the so-called "harmony guidelines", which dictate two-year breaks between six-month operational deployments.
In the event of a major crisis, the structure of the armed forces should enable the UK to mount a large-scale operation (like the 2003 invasion of Iraq), or a second medium-scale operation, for limited periods, while breaking the harmony guidelines.
The operations in Iraq and Afghanistan both qualify as "medium-scale" and "enduring" and this, Sir Jock says, "is not what we are structured for".
His comments, although stark, are not unique. It's acknowledged, across the military and by ministers, that the current "operational tempo" is not sustainable indefinitely.
Last December, Defence Secretary Des Browne admitted that the armed forces needed a period of sustained "regeneration" after four years of constant war.
"The advice to me was that if we maintained this level of operational tempo in the long term," he told the Daily Telegraph, "then the Army's skills would start to degrade. We are not at that stage yet."
Six months later, the tempo has not decreased and so presumably, "that stage" is that much closer.
Members of the Parachute Regiment and Royal Marines Commandos are deploying to Afghanistan's dangerous Helmand province after breaks of just 18 months.
The number of personnel committed to Afghanistan is creeping up, and will soon be over 8,000. Meanwhile, the number in Iraq remains stuck at around 4,000.
The key to reducing the strain on operations is clearly to reduce the presence in Iraq.
An expected draw down in the spring never took place, as the security situation in Basra deteriorated.
But officials now point to the success of the Iraqi security forces in taking control of Basra's lawless streets.
It's widely rumoured that the prime minister will next month announce plans for a complete withdrawal by the end of the year.
In the meantime, the armed forces will continue to live with the extra pain.
It's something they're very good at, but everyone knows they can't keep it up indefinitely.