A lack of testing was one of key the reasons for problems with the £168m tax credit computer system that delayed payments to hundreds of thousands of people, a parliamentary committee was told yesterday.
Problems with existing systems, shortcuts on testing and a lack of IT expertise within the Inland Revenue conspired to create the problems with the project.
The Revenue's tax credit system ground to a halt under the pressure of dealing with the large volumes of data.
IT services giant EDS told the influential Public Accounts Committee that it had "no idea" the failure would happen.
One reason was the reduction of time for pre-launch testing, cut from three months to four weeks, after problems with matching tax credit claimants' names with their National Insurance numbers.
EDS European president Bill Thomas said that, even had a full testing regime been implemented and some of the bottlenecks within the system alleviated, the faults with the transaction management system would still have created problems.
But he claimed that "the problems would not have had such a large effect".
Committee member Frank Fields MP accused EDS of providing a service which was "a disgrace".
But Thomas replied: "It's not as simple as saying 'it's a software problem.' We take responsibility for delivering an unstable IT system. That contributed to the overall problem."
EDS stopped short of criticising the Revenue openly, but the firm is clearly upset over being blamed.
Committee member Richard Bacon said it was clear that the Revenue "did not understand what EDS were capable of delivering".
Sir Nicolas Montagu, chairman of the Inland Revenue, admitted it was "an unpleasant shock that the system was not fit for purpose".
Montagu admitted with hindsight that he would have employed additional consulting expertise to identify potential weaknesses in the project, and make the Revenue "more intelligent customers".
Negotiations on compensation began five months ago but no agreement is in sight.
"We are convinced that we have a case for compensation and will be able to reach agreement without litigation," Montagu said.
The tax credit system will have cost taxpayers £168m to build, of which £12m will be profit for EDS.
IBM and Technical University of Munich team demonstrate how Shor's algorithm, which can't be cracked by conventional computers, can be solved quickly with quantum computing
Hubble Space Telescope finds superflares from young red dwarfs could strip away planetary atmosphere
Younger stars are 100 to 1,000 times more energetic than when they're older
Two of the big four supermarkets will use the system to control sales of restricted products
PUBG news and updates: November's Update #23 to bring new Skorpion pistol and changes to blue zone visibility
Genuinely useful side-arm coming to PUBG in Update #23