The government has, for the first time, mandated a preference for using open source software for future developments.

The new Government Service Design Manual, released as a beta version on 14 March and effective from April, lays out the standards that must be used for all new digital public services developed across Whitehall.

In a section titled “When to use open source”, the manual says: “Use open source software in preference to proprietary or closed source alternatives, in particular for operating systems, networking software, web servers, databases and programming languages.”

Government IT reformers in the Cabinet Office have worked to introduce a level playing field for open source against proprietary software products, which was embodied in the open standards principles published in November last year.

But this is the first time that government IT policy has gone as far as expressing a formal preference to use open source.

The design manual says that proprietary products must only be used in “rare” circumstances.

In digital public services, open source software is clearly the way forward Liam Maxwell, government CTO

“Problems which are rare, or specific to a domain, may be best answered by using software as a service, or by installing proprietary software. In such cases, take care to mitigate the risk of lock-in to a single supplier by ensuring open standards are available for interfaces,” says the document.

Government chief technology officer Liam Maxwell, one of the architects of the new policy, has long been a supporter of open source.

“In digital public services, open source software is clearly the way forward,” he told Computer Weekly.

“Nobody makes packaged software for digital public services. With the software we are making, we have a preference for open source, because it means other countries can use it too and help make that software better. This approach will also ensure we are not locked in to some mad oligopoly outsource,” said Maxwell.

But he added that open source will not always be the answer for every requirement: "We're not dogmatic about this – we'll always use the best tool for the job – but open source has major advantages for the public sector."

Maxwell recently signed an agreement to develop digital public services with Estonia, which has been a leader in using open source to develop government IT systems. Maxwell cited this as an example of the benefits of working with other countries on open source software that each can share and improve.

The design manual also states that any software developed for UK digital public services will be published as open source for others to use.

“For unique needs and common problems which have yet to be solved well elsewhere, develop software by coding in the open and publish under an open source licence,” it says.