As might be expected, the papers devote a huge amount of their coverage to the news that the government has managed to lose the personal information of millions of families.
The Financial Times describes it as "a bleak day for the chancellor, already under pressure over his handling of the Northern Rock crisis and besieged by business for his proposed capital gains tax reforms."
The paper's political correspondent George Parker says up until now Mr Darling has exhibited "quiet confidence" as a minister. But after just five months as chancellor "the government's leading firefighter appears in danger of being consumed by the political flames."
In the Times, crime correspondent Adam Fresco says that the personal information on the discs is enough for criminals to steal goods and money worth "hundreds of millions of pounds."
It quotes a security consultant who says that all the information a fraudster would need to hack into people's bank accounts will be contained on the discs.
"Having a national insurance number is as good as having a passport," says the consultant.
In the same paper, Alice Miles, sums up the outrage and disbelief over the security breach at Revenue and Customs.
"Someone gave a disc containing confidential information about 25 million people to a bloke on a bike? And he lost it?" she says.
The Guardian says that the government was forced yesterday to admit "the most fundamental breach of faith between the state and the citizen" when it lost the data discs.
It discloses that the information commissioner Richard Thomas is now seeking new powers to enter government offices without warning for spot-checks. The paper says Mr Thomas wants new criminal penalties for "reckless disregard of procedures".
The paper's parliamentary sketch writer Simon Hoggart describes the scenes in the House of Commons when Mr Darling told MPs the discs had been lost.
The Tories had an easy target - and made the most of it, he says.
"This wasn't just shooting fish in a barrel - it was harpooning a porpoise that's got into the bath."
The Daily Telegraph devotes nearly four pages of the paper to what it dubs the "Lost Records Fiasco".
Children's charities, it says, fear that the lost information will be "extremely useful" to paedophiles who might target children and pose as their parents.
Its parliamentary sketch describes Mr Darling as looking "paralysed" in the Commons.
His role, says sketch writer Andrew Grimson, is to act as "curator", looking after the legacy of former chancellor Gordon Brown.
"As a mere curator, he cannot do anything serious when water starts to pour through the roof, but can only rush around with his bucket and mop, doing his best to clear up the mess."
The Independent says seven million families are having to make urgent checks on their bank accounts.
The prime minister and his "embattled" chancellor were counting the cost to their reputations, the paper adds.
The Sun's headline is "Skip to the loo my Darling". And it says that the chancellor saw his reputation "going down the pan".
In its editorial the paper says the "eye-popping scale" of the government's latest fiasco "beggars belief".
"Who will trust an incompetent regime which casually allows the confidential records of half the population to be lost in the post?" it asks.
The Daily Mirror is a little more charitable, fingering "blundering officials" as the main culprits behind the loss of the information.
But Kevin Maguire in the same paper predicts that Gordon Brown is poised to "shake up his Downing Street operation, creating a more professional No 10 machine".
The Daily Mail says it is a case of "sheer, mind-blowing incompetence and stupidity... in a class of its own".
Two Fleet Street papers - the Daily Express and Daily Star - do not lead on the data loss story. But the Express asks on its inside pages: "How could ANYONE be so incompetent?" - next to a large picture of the embattled chancellor.