As the UK's budget deficit spirals into uncharted territory – some scenarios estimate it at nearly 60 per cent of UK GDP – the pressure to cut public sector spending seems unstoppable.

The public sector is the UK's biggest buyer of IT and services, so it is natural for this to be the area where politicians look for significant cost savings. And one primary area is software licensing costs.

In February, the government re-launched its policy whereby public sector organisations evaluate open-source software on a par with proprietary software.

At a recent roundtable, public sector organisations, open-source software vendors and analysts discussed the problems of rolling out open-source applications.

Laurent Lachal, research director for open source at Ovum, said the UK government's use of open-source software started warily, similar to the situation in the US, but, unlike the US, didn't catch on until very recently.

"The 2004 paper was launched saying that open source should be used more, but was ignored by the entire sector and the government had to re-launch [in February this year] with a new paper," Lachal said.

Tom Watson MP, at the time the minister for digital engagement, said the reason behind the document's re-launch was to increase the pace of open-source adoption in the public sector.

That increased pace, "to ensure that open-source products are fully and fairly considered throughout government IT", would, said Watson, "ensure that we specify our requirements and publish our data in terms of open standards, and that we seek the same degree of flexibility in our commercial relationships with proprietary software suppliers as are inherent in the open-source world."

Ingres executive vice president of worldwide operations Steve Shine pointed to the recent declaration by the government of Hungary on how it would spend £19m specifically on open-source packages out of about £80m – although half of the budget would still be used for Microsoft packages.

"I don't think ring-fencing a specific amount [for open source] is the right way to do it – when I think of the UK's re-written commitment to open source, I maintain that it is one of the best-written policies out there. The challenge is policing it," he said.

Shine maintains that UK policy is not really an open-source policy. "It's primarily open standards, which means if you use a high-end database and adopt open standards, if you don't like what the vendor does, it is a relatively low-cost effort to replace that database with another vendor’s."

Simon Field, CTO at the Office of National Statistics, agreed that the key is open standards rather than open source. "It all depends on whether you have a political agenda that says you need open source because its open source, or whether you believe that open source will tend to produce better software.

"There's a Darwinian nature to open source which means that if it isn't any good, nobody will use it and it will die, or it will find its niche and thrive, " Field added.

So what are the barriers that prevent deployment of open-source software? Field said it was rarely the IT people but business users. A business buying software wants a piece of paper guaranteeing support and surety, said Field.

"Open source has been successful where comfort factors such as that have been put around the offering, giving business users a feeling of security," he added.

Shine said that over the past six to eight months Ingres has tracked more than a dozen tenders. "However, not one of the tenders reflects the [open-source] policy. There's a disconnect that is not malevolent, it's just that there is no enforcement at all."

Islington Council CIO Jeremy Tuck said that having an open-source policy has not affected the way in which local authorities procure. "There is no real intent, even though the Office of Government Commerce has said it will consider open source."

Tuck pointed to Islington Council's deployment of a document management system. "We simply could not have rolled out a Documentum-type system to 4,000 users in the way we wanted to do it. Documentum would have cost us about £450 per seat, giving us a real licensing concern."

Tuck said that taking into account annual support costs of about £65 per seat, the council had to take a different approach simply because of financial considerations. "If you look at any of the authorities that have rolled out a records management system, the actual amount of users is very small. You have to look at those [licensing and support] costs."

Another issue for public sector organisations thinking of rolling out open-source packages is support. Tuck explained that although large open-source packages such as Red Hat's enterprise stack are quite successful because they are well supported, it is the open-source application layer support that needs addressing. "It's about what support network exists, and there seems to be a support gap," he said.

Bloor Research analyst David Norfolk concurred. "Open source is great, but buying, for example, JBoss, which is well supported and industrial strength, is not the same as going into a less well-supported open-source project."

Asked whether the support network was significantly better for proprietary software, for example from Microsoft, Tuck said there were courses for project managers on how to implement SharePoint architectures. "That level of support is really quite powerful. That is the reality of the market. Remember, there are also lots of Microsoft gold system integrators out there."