UK Edition
British Airways computer chaos: The worst IT meltdowns of all time
This Bank Holiday saw massive disruption to British Airways customers as an IT outage grounded flights, leaving 75,000 flyers stranded.
The problem, put down to a "power surge" by BA chief executive Alex Cruz, is expected to cost the airline £100m in compensation costs.
While headline technology failure scandals, such as the ransomware attack against the NHS earlier this month, are normally the fault of cyber criminals, plenty of IT failures have come about due to human error or poor planning.
As BA attempts to find the cause of its IT disaster, here are seven of the largest technology meltdowns that have crippled businesses and cost millions of pounds.
Terminal 5
Unfortunately, frequent flyers from are more than used to British Airways IT failures ruining their trips abroad. In 2008, the launch of Heathrow's £4.3 billion Terminal 5 was plagued by security delays and baggage mishaps a host of technical problems.
Staff were unable to log in to crucial IT systems, there were troubles with wireless connections and flight data communications, and a lack of server capacity caused systems to freeze, forcing staff to manually sort thousands of bags.
The debacle resulted in 500 cancelled flights and 23,000 misplaced bags. It cost British Airways an estimated £16 million.
London Stock Exchange
The London Stock Exchange has been repeatedly hit by IT woes, but one major outage saw the system down for almost an entire day in September 2008. The problem prevented billions of pounds in trades from being made at the height of the global financial crisis.
It was not the first embarrassment for the exchange. Early plans to automate the market's IT systems cost more than £75m in the early 1990s before the project was abandoned in 1993.
NHS
While the NHS most recently made headlines for bearing the brunt of the WannaCry ransomware attack in the UK, a history of costly IT mistakes has haunted the health service.
An ultimately abandoned £10bn unified patient record system lasted from 2005 to 2013. The programme saw various contractors fail to deliver their systems on time or to budget, with some pulling out entirely.
The project was dubbed by MPs as "one of the worst and most expensive contracting fiascos in the history of the public sector".
AT&T
In a spectacular case of human error, a single incorrect line of code caused half of AT&T's telephone network to go down for six hours in 1993.
A routine restart in New York accidentally triggered a chain reaction that brought down most of the system in seconds. The shut down blocked an estimated 50 million calls in the time it took to rectify the fault. It cost AT&T millions of dollars in unconnected calls.
Knight Capital Group
In a horror story that shows the speed at which IT problems can escalate, financial trading house Knight Capital Group saw one of its algorithms that handled trades start executing millions of transactions on the New York Stock Exchange following a glitch in 2012. The computer appeared to randomly buy shares high and sell low.
The company had accidentally reactivated a disused system for trades after a software update. The problem lasted just 45 minutes, but Knight Capital Group reported a staggering loss of more $440 million - around $10 million a minute.
RBS
A major IT failure at RBS saw more than 6.5 million customers of Natwest, RBS and Ulster Bank hit by problems accessing their accounts over two weeks in the summer of 2012. Customers were unable to access online banking services following a failed software upgrade.
The bank was hit with a £56 million fine from regulators for the failure. It was also forced to pay around £70 million in compensation to customers.
eDreams
One holiday maker was in for a shock when they received a quote from price comparison site eDreams. In 2014, Marion Sessions was hoping to book a holiday to Portugal, but found her final quote was well above the budget flights she had attempted to book. The site had tried to charge her almost £2.7bn for the cost of the holiday.
Fortunately the flyer spotted the error and didn't click "purchase", instead reporting the issue. For the trouble she received a €40 voucher and an apology.