Eric was given the most unglamorous title any bureaucratic committee could have conceived: the system's name stood for External Routing Interface Component.
But it was designed to serve several useful purposes. It would facilitate online filing, which gradually replaces magnetic tapes, floppy discs and paper as the mechanisms by which companies submitted their annual returns.
Over time all companies will be forced by law to file online or by electronic data interchange. And Eric will route all the filed returns to the Revenue's Computerised Operation PAYE system, which holds about 20 million records, the National Insurance Recording system (Nirs2), which holds files on everyone in the UK, and other back-office systems. The process will help cleanse the Revenue's systems of inaccurate data.
Last month Steve Lamey, chief information officer at HMRC, said the department was plagued by very poor quality data. As part of online filing, companies must send data which meets quality standards.
Returns that do not meet these standards will be rejected. Some larger companies have already seen their returns rejected for even minor errors in, for example, national insurance numbers.
But HMRC memos leaked to Computer Weekly advise tax staff that, with Eric delayed, many customers will receive an acknowledgement that their returns have been accepted and fully validated even though they have not passed all of the department's quality checks.
This means the department may have to contact companies later this year, when Eric is fully operational, to correct returns that company payroll staff will have long forgotten about.
Eric was designed to validate the returns but because it has been delayed the department is using a system called FEC - front-end contingency - mainly to acknowledge the receipt and acceptance of returns.
Disclosures in leaked HMRC memos do not entirely agree with what the Revenue has told Computer Weekly. In its statement the department said it was applying quality standards to returns.
But one HMRC internal memo, dated 15 June 2005, said, "Returns will all be accepted as correct and an acceptance message will be sent to the submitter. When Eric is available to process these returns, quality standard 2 and quality standard 3 checks will be applied."
HMRC did, however, make an apology. "We accept that delays to Eric may mean that we have to go back to employers later than usual, and we are sorry for that."
But the department is convinced that Eric is in no danger of being added to the list of government IT disasters.
"Eric went live and is now processing returns in a controlled go-live. And the results are looking good, indicating that Eric is fulfilling all of its design functions properly."
Tax staff hope the Revenue is not now showing the misplaced optimism that led to its publicly declaring tax credits as a major success when the project was actually at its nadir.