The Cabinet Office has “requested” that NHS chief information officers obtain central clearance before buying Microsoft products until a national procurement contract is signed with the company.

Purchases of “non-business critical” products from the IT giant, including upgrades to existing software packages, should be approved centrally, the government advised.

Information chiefs around the country were contacted by the Cabinet Office via email during the last four weeks.

Crown representative Stephen Kelly, who is leading negotiations for the government, wrote: “It is my intention to develop a commercial arrangement with Microsoft which will provide better commercial terms, reduce cost and add greater flexibility.

“The focus of the government in its engagement with strategic suppliers is to act with one voice to secure the most favourable terms, therefore I ask for your continued support during this process and that you refrain from non-business critical spend with Microsoft until a new commercial arrangement is secured.”

The email was unspecific about whether the discussions were only about licences for products such as the Windows operating system or Microsoft Office, which are typically bought in bulk nationally, or whether specialist health packages such as Amalga and HealthVault were included.

This has frustrated information chiefs, who are now unsure what they should buy, or how long they will have to wait to upgrade their systems.

One chief information officer said: “I read it to mean that if we’re planning to do anything big, wait for future news about these discussions.”

Another told HSJ: “Some organisations are not in a position to wait – and they may wait for six or 12 months and then find that what they were waiting for wasn’t included [in the deal] anyway.”

The Department of Health pulled the plug on its 12 year, £500m enterprise-wide agreement with Microsoft last summer.

In April the Cabinet Office appointed “crown representatives” to manage deals with 35 companies, to ensure that the government acted as a single customer instead of having separate deals for each department.

A Cabinet Office spokeswoman said: “The Cabinet Office is not asking chief information officers to stop buying anything.

“We are requesting that departments route all potential purchases through the centre so we can assess each case on its individual merits.

“Where the spend is business critical, and Stephen Kelly, the crown representative, has had visibility of it, departments are able to make purchases.”

She said this would remain the situation “until further notice”, and that “the engagement with Microsoft covers all government licensing and packages”.

A Microsoft spokeswoman said: “Discussions with government are, and have always been, business as usual for Microsoft. We do not comment on these private negotiations publicly.”