The number of people held in jails in England and Wales has reached a new high, the Prison Service has said.
The number of people in prison has never been higher
On Tuesday it said the number of inmates had reached 74,543 - up 2,167 since 2 January, and nearing capacity.
In just one week last month the prison population increased by 597 - enough to fill a medium-sized jail.
The Prison Service said there were just 600 jail places left, and that it was looking at the possibility of keeping extra prisoners in police cells.
The new high is 83 above the previous record of 74,460, reached on 18 November last year.
A Prison Service spokeswoman said: "We are monitoring the situation.
"We are looking at the options, including police cells and getting any out-of-commission cells back into use as quickly as possible."
Director of the Prison Reform Trust, Juliet Lyon, said the news that prisons were "on the brink of safe overcrowded capacity" should set alarm bells ringing for the government.
She said: "To avoid a crisis, it must act now to divert petty offenders into effective community penalties, addicts into rehabilitation and the mentally ill into the health system."
It called for an end to "excessive sentence lengths" and "needless use of custodial remand".
The charity said official records showed 81 jails were overcrowded at the end of January, with 11 exceeding their maximum capacity.
It said basic conditions were deteriorating in a number of jails with prisoners sharing cramped cells with an unscreened toilet,
unable to access showers or exercise.
Liberal Democrat home affairs spokesman Mark Oaten said the situation was a "national disgrace".
He said prison numbers would continue to increase "unless the government tackles the revolving door problem", through education.
Last year the Prison Reform Trust said tough sentencing by judges, rather than a rise in crime, had led to the record prison population.
JAILS EXCEEDING CAPACITY
It said a 71% rise in the prison population between 1991 and 2001 was due to a "misplaced emphasis on toughness", with courts sentencing more people to prison and for longer terms.
But the country's top judge claimed political interference into sentencing was to blame.
Lord Chief Justice Lord Woolf blamed the record number of inmates on political initiatives and a distrust of judges imposing jail terms.
It almost emerged last year that the proportion of people in prison in England and Wales was the highest in the whole of western Europe.
Home Office figures showed that for every 100,000 people, some 139 are imprisoned - which is more than in Libya, Malaysia and Burma.