Speaking at last week's Institute of Revenues, Rating and Valuation conference in Torquay, Sir William said much of what the committee was told during its local government inquiry 'didn't convince me that, when the chips were down, [whistleblowing] guarantees would hold'.
He argued that the provision of whistleblowing procedures was 'one area which we don't believe is sufficiently well developed in local government'.
Sir William, formerly the chief inspector of the government's Social Services Inspectorate, said he would wait to see 'whether whistleblowing people will be promoted and credited rather than made to walk the plank'.
But Sir William said there was still much to be concerned at and 'scarcely anyone had a good word to say about the code in its present form'. He cited the committee's recommendation that local codes should be developed, reflecting a model code, together with a new local government appeals tribunal.
He noted that planning was a 'powerful focus of discontent' and had become associated with 'corruption, incompetence and procrastination'. He said councillors needed to be offered training in planning issues.
Sir William reaffirmed Nolan's opposition to surcharge, calling it an 'archaic penalty' which should be abolished and replaced with an offence of misuse of public office.
Councillors' allowances was one area of local government where the committee had no criticism of the present system, Sir William told delegates. He said that, while any system of allowances was open to abuse - and that some MPs had often falsified their expenses - 'no councillor would seek election to get rich'.