For a man who openly admits "we have our fingers crossed", the Bank of England's new deputy governor with responsibility for monetary policy, is showing a tendency to spout some dangerously mixed messages about the economic challenges we currently face.

At the beginning of this week, while enjoying the mountain air at the Kansas City Federal Reserve's annual symposium in Jackson Hole, Wyoming, Charles Bean gave a widely-reported interview to BBC Radio. The important thing he wanted us all to realise, he claimed, is that "this is just a temporary period of subdued growth". We will, he went on, "get through the other side and growth will resume to more normal levels".

Modestly reassuring. But against a backdrop of the first quarter's standstill in UK output after 63 consecutive quarters of continuous growth, the Bank's former chief economist also contrived to leave the impression that the challenges we face are at least as severe as the 1970s, perhaps even as significant as the Great Depression of the 1930s.

His words were interpreted, not just as a warning that things could be tough for some considerable time to come, but that social trauma would result for millions of families. So what's it to be? A mere blip in the onwards and upwards story of growth? Or a return of soup kitchens for the jobless and wealth destruction on a massive scale?

That central Bean message of a temporary period of subdued growth is pretty much in line with what his boss, Governor Mervyn King, aspired to, when he delivered the Bank's latest quarterly inflation report a couple of weeks ago. "We will return," King concluded, "if not to the nice (non-inflationary, continuous expansion) decade, then at least to one that, as central bankers say, is not so bad."

Hard-pressed families across these islands might settle for a period of subdued growth, even a not-so-bad decade ahead. But if the price for getting there is suffering 70s-style hyperinflation and mass unemployment, they might want to ask whether the best central bankers can do meantime is keep their fingers crossed.

A careful reading of what Bean actually said to the BBC shows his references to the 1970s and the Great Depression were aimed at putting the scale of the shocks currently reverberating around the global financial system in some kind of historical context. Others, from the IMF to George Soros, have done the same.

But Bean's fusillade of references to the grimest of economic times past, complete with a warning of more "grenades" waiting to explode, was bound to be taken up as an admission that, while fingers are crossed for a more benign outcome, the consequences could prove much bleaker than that.

Central bankers were no more adept than their commercial counterparts in seeing this crisis coming. Is it too much to ask that, as they respond to it, they exercise a little more care than Bean has shown in this particular intervention, in sorting out their message on the scale of the challenges they think they face from their message on what the consequences might be for the rest of us if they fail to steady the ship?

As Keynes observed in 1931, during the Great Depression, "A sound banker, alas, is not one who forsees danger and avoids it, but one who, when he is ruined, is ruined in a conventional way along with his fellows, so that no one can really blame him."

There is plenty of blame avoidance going on in today's banking circles, both central and commercial. At that same Jackson Hole symposium, Federal Reserve chairman Ben Bernanke highlighted the "too-big-to-fail" conundrum. Bernanke acknowledged that particularly thorny issues are raised by the existence of some banks and related financial institutions that are perceived as too big to fail because of the wider consequences if they did go to the wall.

The Fed chairman conceded that its decision, in March, to prevent the default of Bear Stearns had added to the problem, widening the safety net and, in the end, encouraging even more excessive risk-taking and yet greater systemic risk in future. The Fed's promise is to come up with a more effective system of regulation in future, to prevent a repeat. But we have been there many times before.

The too-big-to-fail mindset is well entrenched. An hour after that Charles Bean interview was broadcast on Monday, former Bank of Scotland governor Peter Burt appeared on the Today programme to argue, in effect, that there is no alternative. Shareholders and bank executives can and should pay the price of excessive risk taking. He suggested, but failing banks themselves must be rescued. The alternatives are too terrible to contemplate.

That position would hold greater credibility this side of the Atlantic if more failing bankers, like their counterparts over there, paid for excessive risk taking with their bonuses and, ultimately, their jobs.

But until they do, we could do with more measured debate over here about the future path of banking regulation, and less finger crossing and spectre-raising, Bean style.