Microsoft's Office software has been the mainstay of UK government for years, but that could be about to change.
A senior UK government minister today spoke of measures to "break open Whitehall's lock-in to proprietary formats" so the administration could start using a much broader range of applications.
If UK government were to end its reliance on Microsoft products, which is how the comments are being interpreted, it would have far-reaching consequences for the Redmond-based software giant.
Beyond the loss of revenue from Whitehall, the UK government sector has reportedly spent £200m on Microsoft Office since 2010, any large-scale switch could shrink demand for Office among the general public and government workers.
For years government departments have expected people who interact with them to use Microsoft products. Even for unavoidable tasks, such as paying taxes, there has been the assumption that Microsoft software would be used, as seen by the Microsoft Excel spreadsheet the UK tax authority HM Revenue and Customs provides as a template for a tax return.
In a speech at a conference in London today, UK Cabinet Office minister Francis Maude signalled the government wants to move away from tying government staff or taxpayers to any one piece of software or technology.
"The software we use in government is still supplied by just a few large companies. A tiny oligopoly dominates the marketplace," he said.
"I want to see a greater range of software used, so civil servants have access to the information they need and can get their work done without having to buy a particular brand of software.
"In the first instance, this will help departments to do something as simple as share documents with each other more easily. But it will also make it easier for the public to use and share government information."
The government is a long way from ditching Microsoft Office in favour of an open source alternative, but is is laying the groundwork to allow such a shift to take place.
At the end of last year the government revealed the first open standards that departments will be required to use when swapping electronic information.
These standards are designed to ensure government and the people it communicates with are not forced to use a particular proprietary technology. Government is currently consulting on which document formats should be mandated when it shares information with the public. Standards being considered are pdf, txt, doc, odt, xlsx, odp and html.
"Technical standards for document formats may not sound like the first shot in a revolution," Maude said.
"But be in no doubt: the adoption of compulsory standards in government threatens to break open Whitehall's lock-in to proprietary formats. In turn we will open the door for a host of other software providers."
Mark Taylor, CEO of open source software services company Sirius and former chairman of the Cabinet Office's new suppliers to government working group, described the drive to set open standards as an attempt to rebalance the playing field so other software vendors could get a foothold in UK government bodies.
"The Cabinet Office can't force the rest of government to ditch Microsoft Office and adopt Open Office and LibreOffice," he said.
"It's more about mandating the use of open document standards and letting the market sort itself out."
For some time the Cabinet Office has made documents available online in odf and pdf formats, as well as Word documents.
"I suspect that will end up being the default practice across government, that they will insist on using genuinely open office formats that can be run outside of Microsoft Office," Taylor said.
Various central government departments have also been trialling the use of open source OpenOffice and LibreOffice suites for a while, and open source operating systems are in use at various public sector bodies, including the Met Office and Government Digital Service.
But it will likely be years before any large-scale move away from Microsoft Office by UK government, due to departments relying on countless documents stored in proprietary Office formats and macros designed for Word and Excel, Taylor said.
"I don't think you could get government departments shifting off Microsoft Office overnight, lock-in is lock-in and they have been locked in. It is a multi-year proposition," he said. However, he added that the sort of challenges that would be faced are not insurmountable.
"The world faced this problem once before, with a generation moving from WordPerfect to Microsoft Word.
"The truth is that different generations of proprietary software have faced the same challenge, going from Office 95 to Office 2003 there were formatting errors and challenges in macros. It is a factor in migrating any software."
Different UK administrations have also made strong commitments to upping the use of open-source software for years, to little effect. The latest were guidelines stipulating that open-source software must be the first choice for all new UK government projects, laid down in the Government Service Design Manual last year.
Other government bodies in Europe have successfully moved to open source software, most famously the city of Munich, which recently completed its transition of about 15,000 staff from a Microsoft OS and office suite to open source alternatives, and the French gendarmerie.
A Microsoft spokeswoman said: "Microsoft supports the UK government's drive to reduce IT costs and promote the effective use of information technology to reduce its operating costs everywhere."