The second article, headlined "The hounding of Baskerville", said she had used her Twitter account to repeat a message reading "Nick Clegg sold out faster than Muse".

The civil servant said she regarded the material as private but both papers argued the posts could be read by anyone and not just people who chose to follow her feed.

They also said the nature of some of the messages raised questions about the civil service code on impartiality.

PCC director Stephen Abell said: "This is an important ruling by the commission.

As more and more people make use of such social media to publish material related to their lives, the commission is increasingly being asked to make judgments about what can legitimately be described as private information. In this case, the commission decided that republication of material by national newspapers, even though it was originally intended for a smaller audience, did not constitute a privacy intrusion."

The commission ruled there had not been a breach of clause three of the Editors' Code of Practice, which covers privacy.

It said the publicly accessible nature of the information was a "key consideration".

It is the first time the Press Complaints Commission has ruled on the republication of material from the micro-blogging website.