A lot of mad dreams were dreamt in those first days after the Conservatives took power in 1984, when it must have seemed to their admirers all things were possible. And of all, the maddest were the designs of a group of prominent businessmen calling themselves the Committee for the Responsible Privatization of the CBC.

Much has changed since then. The idea of the government handing over the CBC to the private sector on request now seems quaint. But what if the proposal were to come from within the corporation itself? Is it possible the CBC's directors and staff might themselves come to believe they would be better off free of the public sector?

This sort of speculation is occasioned by the arrival of the latest wave in the eternal cycle of complaints about the ''threat'' to public broadcasting. This time around, however, the threat is twofold: spending cuts announced in the last budget, and the CBC's new ''journalistic policy,'' forbidding on-air staff from politicking in their free time.

As ever, some considerable exaggeration and misrepresentation is at work here. The cut in the CBC's subsidy is invariably reported as amounting to a ''total'' of $140 million over the next five years. In fact, the corporation's parliamentary allocation is to be increased by $58 million next year, to $965 million. The year after that, it is to be cut by $20 million, then by $10 million more in each of the three following years.

If you add up these cuts, you certainly get $140 million, but this is meaningless: one might as well say Parliament has voted to give the corporation a ''total'' of almost $5 billion over the next five years. The corporation's budget is set on an annual basis, and the most it could be said to have been cut is by $50 million - from the 1990 level.

HARDLY BUTCHERED

Now, $50 million is not peanuts, but it hardly means the CBC has been ''butchered,'' as outgoing president Pierre Juneau would have it. Good grief, the CBC misplaces that much in its financial statements.

Nevertheless, from within the corporation come the same sort of threats of self- mutilation that a public agency facing budget restraints resorts to: abolishing Radio Canada International, putting commercials on The National, even reducing Canadian content.

The intolerable ''journalistic policy'' was hastily produced last year as a sort of anti-bias condom in the corporation's consuming lust for the all-news network license. It has already provoked the resignation of Man Alive host Roy Bonisteel and forced Cross-Country Checkup host Dale Goldhawk to quit as president of the Alliance of Canadian Cinema, Television and Radio Artists.

This is no more than the sort of constraint that people in many other positions face. Absolutely no one is forcing these people to take these highly paid sinecures. If it is that vital the world hear the private thoughts of Roy Bonisteel, then the choice is his.

The issue is not whether the outside associations of CBC journalists might taint their objectivity - no one believes that they have any. Rather, it is the prestige and credibility their CBC positions afford them in the wider world that is at stake. Roy Bonisteel, private citizen, will carry about as much weight on an issue as any similarly earnest fellow might. Roy Bonisteel, TV journalist, carries a good deal more, thanks to the taxpayer. The public should not have to underwrite a private political agenda with which they may sharply disagree.

But let us suppose these matters are as grave as they are painted. It might occur to those protesting that these are the inevitable results of public ownership. Sooner or later, all public agencies run into problems of ''underfunding,'' depending on the political winds prevailing.

It is impossible to conceive of a public medium of communication, similarly, long being permitted to operate without some strictures on its editorial freedom, whether it be that it follow one political line or that it follow no political line. But free the CBC of the bonds of public ownership, and both of these frustrations vanish.

So here's my suggestion: put the CBC on pay. Let it charge a subscription fee, instead of having to come to the government for funds. Six million subscribers at about $12 a month would replace present subsidies.

If the government wanted to be tricky about it, it could require all cable subscribers to take CBC. A higher fee, and the CBC could keep commercials not only off The National, but off the air altogether. Best of all, Roy Bonisteel could return, conscience intact.