The history of NHS 24 has been difficult, to say the least.

In its early stages, the 24-hour service, which handles calls to GP surgeries outwith normal opening hours, struggled to cope with the level of calls and, during the first winter, patients were forced to wait hours for nurses to ring them back.

For some years afterwards, a persistent lack of confidence surrounded a vital public service.

Successive managers at NHS 24 have done their best to improve the situation, by working more closely with area health boards, for instance, but the image of the helpline is unlikely to be improved by the news in The Herald today that a proposed new computer operating system has been delayed.

The £27 million system was supposed to improve the service by making the calls quicker and giving NHS 24 more flexibility in the way it works. The costs of the new technology were also expected to be lower, saving the NHS money.

However, none of these improvements has happened and, furthermore, it is not clear when they will. Tests carried out on the system have identified fundamental issues which means the original plan to roll out the technology to four call centres last autumn has been pushed back indefinitely.

It is a serious blow for NHS 24. By definition, routine testing is designed to throw up problems that can be ironed out and this may be what has happened in this case, but the delay raises some profound questions about the service and how it works.

The first is around the motivation for the new technology. NHS 24 says it is to improve the service (a consultation service was completed with patients and staff) but the fact it will also save money raises the suspicion that reducing costs was the driving force.

The second question is over who will operate the new system. For many years, a proportion of calls to NHS 24 have been dealt with by call handlers who are not medically qualified - and, with proper precautions in place, that has been made to work - but the public will want reassurance that, under the new system, medical advice will be given out only by people with proper medical training, especially if the number of questions callers are asked is to be reduced.

The third area of concern is about the new free number 111, intended to operate with the new system. The new number is fine in principle as it is easy to remember but problems could arise if NHS 24 finds that it is too easy to remember and there is a surge in calls. The service has not been ready for that in the past but it must be this time.

There are other questions about the cost of the delays and exactly how long those are likely to be. These questions need answers as promptly as possible. With more than one million calls being handled by the service every year, running NHS 24 is not easy and, if new technology can make the service quicker, it should be welcomed. But the delays to a system designed to make NHS 24 better will shake public confidence in this vital service; confidence that it has taken years to build up.