In the final months of 1999 concern grew into panic that the millennium bug was going to cause computers to malfunction and potentially endanger everything from tills to power stations. It didn't happen quite like that, but the public safety warnings from the time remain intriguing.
The eight-page pullout that Action 2000 placed in British newspapers in 1999 is a snapshot of the technology in a home at the time.
The government-backed advice booklet warns what to do about video recorders, answer phones and fax machines. The illustrations are of cathode ray tube computer monitors.
The bug had first been predicted years before. An article in Computer World magazine in 1993 was one of the first to attempt to bring it to a wider audience. "Have you ever been in a car crash?" the article asked. "Unfortunately, unlike the car crash, time will not slow down for us. If anything, we're accelerating toward disaster."
The bug was about the limitations of the clocks inside computers. Since the 1960s computers denoted years such as 1998 as 98 to save memory. As a result, when the new millennium arrived, it was expected many computer clocks would see 00 and understand that to mean 1900.
"All of a sudden your business logic wouldn't work," says Ross Anderson, professor of security engineering at Cambridge University, of the threat. "The time of an invoice, delivery, transaction or any of the other 101 processes a business has is thrown completely off".
In 1993, a newsletter called "Tick, Tick, Tick" ran a "worst-case scenario contest" which sought "the most creative ideas of what could happen on 01/01/2000".
Many governments took precautions and in the UK and elsewhere they went further than just concentrating on business and key infrastructure - ordinary homeowners were drawn in too.
In the UK Action 2000 was set up to warn and to prepare. Electronic machines needed to be "year 2000 compliant". "Your business is in danger" a leaflet stated in large yellow letters. But the message was still restrained - "the very worst that can happen is that some [computers] may get confused over the date".
Its millennium bug "home check" pullout sought to explain. "Check your PC with our simple 5-layer Bug Test," it said.
But it was also an attempt to dispel myths. "Very few household appliances are affected," it explained. "Lawn mowers, hedge trimmers, rotovators, barbeques [and] swimming pool equipment" are confirmed as safe.
1 January, 2000: Minor bugs
- US - Official timekeeper, the Naval Observatory, reported the date as 19100 on its website
- Japan - system collecting flight information for small planes failed
- Australia - bus ticket validation machines failed
- US - over 150 slot machines at race tracks in Delaware failed
- Spain - worker was summoned to an industrial tribunal on 3 February, 1900
- South Korea - district court summoned 170 people to court on the 4 January, 1900
- Italy - Telecom Italia sent out bills for the first two months of 1900
- UK - some credit card transactions failed
In the popular memory, the millennium bug was something that failed to come to pass. Most forget that there were consequences. In the UK, the bug was blamed for more than 150 pregnant women getting incorrect results for tests for Down's Syndrome.
And while the wilder predictions in the media did not come to pass, those who worked on informing the public feel they acted sensibly and proportionately at the time.
"We achieved our aim," says Gwynneth Flower, who was the managing director of Action 2000. "There were a few eccentrics. One woman virtually moved her whole family to a remote house in Scotland, with water only from a well at the bottom of the garden, because she thought it would be Armageddon."
Traditional advertising was used, but also lectures in schools. We "explained it to them so they go and tell mummy and daddy, and ask what they were doing to prepare".
Take-up in some areas was slow. Even within the government. In 1999 a report from the National Audit Office warned that there was a "wide variation in progress" by local authorities.
Some found the preparations excessive. "It was an astonishing incident," says Anthony Finkelstein, professor of software systems engineering at UCL.
But its implications were described by Tony Blair at the time as "one of the most serious problems facing not only British business but the global economy today". Margaret Beckett, then the minister in charge of millennium preparations, said the bug had the capacity to "wreak havoc".
"I think there was a lot of hyperbole in the press. Part of our job was to keep on top of the hype" says Paddy Tipping, then minister for the millennium bug. "We had to downplay it and persuade people there was a strong government initiative working. Many people made their names saying it would be a catastrophe."
But Finkelstein says it was political. "The cost of political overreaction is smaller than underreaction. It was a confluence of politics, commercial money, journalists who had a story too good to check and local interest."
But the work was "crucial", according to Flower. "With hindsight it is easy to say there was not a problem. Now we take all our vital services and their interdependencies for granted.
"One of the banks we worked with confessed it was still processing all its transactions in pounds, shillings and pence with adjustments added on later. British Telecom has said some of its exchanges would have crashed. It only takes a tiny fault and the whole lot comes crashing down."
The result was never going to be the catastrophe some predicted, says Tipping. "I spent the worst New Year's Eve of my life in the Cabinet Office. We could see that there hadn't really been any problems in Australia or the Middle East already. We were never in crisis mode. It was a case of a job well done."
But was that down to good prevention or the lack of a problem in the first place?
"The reaction to what happened was that of a tiger repellent salesman in Golders Green High Street," says Finkelstein. "No-one who bought my tiger repellent has been hurt. Had it not been for my foresight, they would have."
"If there is one thing I am trained to recognise it is un-evidenced assertions not based on empirical analysis," he says. What no one did was look "at the background level of systems falling over", he suggests. "Yes some things went wrong. But they always do."
Had no preparation been done for the bug, says Anderson, "lots of stuff would have broken". But the damage would in most cases have been minor and easily repaired. Armageddon it wasn't.