The Government had concerns that Microsoft’s Open XML format would hurt vendor independence, documents reveal.

The Cabinet Office opted for Open Document Format (ODF) for all future document collaboration and sharing yesterday, and PDF/A or HTML for viewing government docs.

Microsoft attacked the move, saying the benefit for UK citizens was "unclear" after its own OOXML format was rejected.

However, minutes from the Technical Standards Panel, which discussed which open standards format to adopt, reveal the Government has misgivings over Microsoft’s format.

It said that Linda Humphries, the Government Digital Service (GDS) expert on open standards, dismissed Open XML over fears around having little flexibility between suppliers, while ODF met open standards requirements better.

The minutes stated: "For OOXML, there were concerns relating to the vendor independence and market support criteria – particularly with differences between transitional OOXML and strict OOXML conformity."

A Microsoft spokeswoman previously said: ""Microsoft believes it is unproven and unclear how UK citizens will benefit from the government’s decision.

"We actively support a broad range of open standards, which is why (like Adobe has with the PDF file format) we now collaborate with many contributors to maintain the Open XML file format through independent and international standards bodies."

Labour shadown Cabinet Office minister Chi Onwurah told CBR earlier this week that a Labour government would want a "mixed economy of suppliers".

The GDS is charged with helping departments adopt the new open standards, which became effectively immediately.