It has boasted of leading a 'radical revolution in local government transparency'.

But it seems Hammersmith and Fulham Council isn't as open as it claims after it was found to have one of the worst records in responding to freedom of information requests in a study of 33 public authorities.

It now faces regulatory action from The Information Commissioner's Office (ICO) for 'transparency delays', after it failed to heed demands to increase its response efficiency.

Just three other local authorities were found to be similarly poor following the study, which was conducted by the ICO between October-December last year, and the offenders have now been forced to sign an undertaking to improve their performance.

Information commissioner Christopher Graham said other councils monitored had maintained or improved their response performance.

"I am delighted that over two thirds of the authorities whose performance we have been monitoring have managed to overcome their problems," he said.

"However the remaining have not done enough to convince us they have a clear and credible plan for getting back on track. Over the next four weeks we shall be discussing appropriate steps with them."

Last July, H&F council leader Stephen Greenhalgh hailed the authority's openness after it started publicising its expenditure online.

He said at the time: "We want to be champions of openness and transparency."

Councillor Harry Phibbs insists that is still the case and blamed the volume of FOI requests the authority recieves for its poor performance.

He said: "We are 100 per cent committed to answering freedom of information requests as quickly as possible. However, as an extremely high profile borough and the former Council of the Year, we receive a particularly high number of requests.

"We already spend at least £200,000 on dealing with FOI requests for information every year. The number of requests has been almost doubling every year - in 2010 we answered 969 enquiries up from 203 in 2005."

He added: "This council has led the way in openness and transparency by being one of the first authorities in Britain to put all spending above £500 on-line."

The three other poor performing local authorities were Westminster, Islington and Wolverhampton, while there were also concerns over the Cabinet Office and Ministry of Defence.

The ICO is continuing its study and expects to complete it by June.