Microsoft has decided to allow governments and international organisations access to the source code for Office 2003.

The company will offer governments access to the code under a shared source licence as part of its Government Security Program. The UK government has already signed up, Microsoft confirmed.

The decision is aimed at shoring up confidence in the security and inter-operability of Microsoft software as it faces stiffer competition in the public sector from rivals including Sun, which has been touting growing support among governments for its open-source productivity software, dubbed StarOffice.

Microsoft has long offered governments access to source code for its Windows desktop software but recently suggested it may disclose more about its products. Last year, it began allowing governments access to Office 2003 XML Reference Schemas, so they could incorporate them into their own software to improve the inter-operability of Office documents. Under the new shared source licence, governments will now get related technical information and participants will discuss existing and future projects related to the software.

Recently, Microsoft has also sent signals that it may be willing to co-operate more with rivals. Under a litigation cease-fire sealed with Sun earlier this year, Microsoft said it would look for more ways to work with developers of the Open Office open source project, although it has reserved the right to sue them for patent infringement.

Microsoft's expansive gestures appear to be geared toward keeping a firm grip on the public sector, which often awards the largest software contracts in a country. The software maker said that more than 30 countries have already signed onto its Government Security Program.

A UK government spokesman said in a statement that the Office 2003 shared source licence would help it understand the security implications of Office, allowing it to deploy the software more ecurely in a variety of scenarios.

That Microsoft has signed up the UK government as one of the first program participants comes as little surprise, given their historically close relationship. The UK's Office of Government Commerce (OGC), which negotiates volume deals for the public sector, signed a three-year licensing deal with Microsoft in 2002 to provide desktop software for almost 500,000 public servants.

Furthermore, the government is putting final touches on a deal to renew the agreement, which an OGC spokesman characterized on Monday as "imminent".

Microsoft released news of the Office licensing program from Europe, underscoring the importance it places on winning big government deals in the region. Government bodies in Germany, Hungary, France and Italy have all recently thrown support behind open source initiatives, putting pressure on Microsoft to work harder at winning public sector contracts in Europe.