Facebook admitted this week that it hired a high-powered public relations firm to smear competitor Google, using what one insider calls furtive and creepy tactics.

The social-networking site admitted on Thursday that it hired WPP owned PR firm Burson-Marstellar to focus attention on the use of consumers' personal data on Google Social Circles, one of Google's less known social networking features.

The tactics were questionable, however, says Burson-Marsteller's former UK chairman.

Terence Fane-Saunders, who worked for Burson-Marsteller in the 1980s and now runs his own PR firm, Chelgate, wondered what on earth happened to the firm, criticizing their tactics.

If senior B-M professionals are now seen to be operating like shadowy, backstreet spin merchants, you have to wonder about the continuing value of that example, he said.

Burson-Marsteller confirmed on Thursday that it was secretly hired by Facebook to run an anonymous campaign against Google.

It contacted several journalists and privacy experts without revealing the identity of its client.

In this grubby little attempt to seed negative stories without disclosing their source, they were denying the media (and that means the public, and that means you and me) the opportunity to assess the value of those stories, Saunders said. If you don't know the source, you can't judge motive.

Responding to the backlash, Facebook said it should have presented the issues in a serious and transparent way.

We wanted third parties to verify that people did not approve of the collection and use of information from their accounts on Facebook and other services for inclusion in Google Social Circles, the company said in a statement.

Burson-Marsteller said on Friday that it would not fire the two ex-journalists involved in the smear campaign - former CNBC technology correspondent Jim Goldman and former political journalist John Mercurio - who joined the PR agency relatively recently after long careers in the media.

The pair will receive receive extra training and Burson-Marsteller said it intends to redistribute its code of ethics to all employees in the wake of the scandal.

We have talked through our policies and procedures with each individual involved in the program and made it clear this cannot happen again, said Pat Ford, Burson's USA president, in an article in PR Week USA.