He has advised lawyers and media organisations to withdraw from it.
This is the latest blow to the reputation of the PCC. In November, Alan Rusbridger, Guardian editor, resigned from its code committee after if failed to rule in favour of The Guardian over its phone hacking investigation.
Rusbridger said last night that the PCC's credibility was clinging by its fingertips.
Other voices have criticised the PCC recently. Roy Greenslade described it as an effective mediator of the regional press, but less effective at regulation.
The PCC has been a bit flat-footed in its response to serious criticisms like this, some might say arrogant. It needs to heed such voices.
A new Parliament will be elected this year, and one which will perhaps have more of an appetite for statutory regulation. Criticism like that of Sir Ken MacDonald should be regarded as fair warning.