Overcrowded prisons, inmates stuck in their cells for 23 hours a day, prisoners spending nights in police stations - these are recurring problems for Britain's creaking criminal justice system, but the possible solutions are increasingly limited.
Magistrates and judges are sending more people to jail for longer
The number of prisoners has been rising steadily for over a decade.
There are 25,000 more people in jail now in England and Wales than there were in 1995. There's also been a significant rise in Scotland's prison population, which now stands at about 7,000.
Criminologists, politicians and penal reformers have written volumes on the likely reasons for the increase.
Different patterns of offending, a more punitive climate of opinion, tougher legislation, demographic changes, more crime - all have been suggested, and at least some are correct.
The bottom line, however, is that magistrates and judges are sending more people to jail for longer.
What appears to have caused this more recent, sudden surge in prison numbers over the past few weeks is something of a mystery.
Seasonal fluctuations due to more court cases being heard only partly explains it.
One possibility is that more offenders on community sentences and those freed on licence are being recalled to jail for breaching their conditions of release.
The Probation Service has certainly been encouraged to bear down on them.
There are about 5,000 people in jail who are in this position, and decisions as to whether or not to release them again are taking longer than expected.
Another theory for the "spike" in the prison population, as the Home Office minister Fiona MacTaggart calls it, is that the London bombings in July have triggered a harsher approach to sentencing by the courts.
In 1993, the murder in Liverpool of two-year-old James Bulger was followed by a large rise in prison numbers, as the mood of public opinion changed.
Over the years, as speeches by politicians and new laws emphasised the importance of imprisonment, the increase continued.
Could it be - just as in 1993 - that as a result of the July attacks sentencers have become a bit less inclined to give defendants the benefit of the doubt?
No one can prove it, but the rhetoric and anger expressed in the aftermath of the bombings cannot have gone unnoticed by those dishing out the punishment.
As for solutions, building new prisons is not an option the Treasury can afford.
There are new places becoming available - about 1,000 over the next 18 months in refurbished wings and new units in existing jails - but that may not be enough to keep pace with the increase.
Lower re-offending rates would help of course, but that takes many years.
More use of community sentences is what the government would ideally want to see, but for dangerous criminals it's not possible. Besides, if offenders don't adhere to the conditions, they'll end up in jail.
In the short-term, there's only one answer - release more prisoners early on an electronic tag.
But freeing some inmates six months before the end of their sentence - an option ministers are thought to have considered - would be political dynamite.
Which is why police cells are being used - an emergency measure to cope with a shortage of places in London and the West Midlands.
It's not pretty - but at present it's the only way.