Two high-profile government IT projects are running months behind schedule.
The Public Records Office (PRO) has admitted that the 1901 census won't be back online until next month at the earliest.
The website has been offline since January, when it was closed after experiencing unprecedented demand. A statement on the PRO site said that QinetiQ, which developed the site, is still testing the service.
The PRO is also carrying out its own independent test programme. "The final testing is underway and we anticipate that it will be completed by the end of July," it said.
"If the results of the testing programme are positive it will be possible to know whether the service is sufficiently robust for it to go live."
But a PRO spokesperson admitted: "The nature of the testing is such that it throws up issues that need to be addressed, and on occasion requires tests to be re-done.
"This has meant that we cannot give a firm date for the return of the 1901 census online service."
Enhancements to the site include increased bandwidth, dedicated firewalls at the internet service provider to protect the site, improved load balancer configuration to divert overload, and an additional database server engine.
It has also been revealed that the development of new systems for the Child Support Agency, due to be in place by April, is still delayed.
The Agency explained that the testing of the new IT system for child support reform is progressing, but did not give a date for its completion.
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