The resulting shift to international transparency was surprising both in its speed and wide range. Scores of tax information exchange treaties were signed in 2009, and even Switzerland and Liechtenstein adopted the OECD's disclosure regime. Switzerland has since gone farther and declared that its financial sector will no longer handle undeclared funds.

While the system was absorbing this shock, STEP commissioned a survey of wealth management professionals, seeking their views on how the transparency revolution would affect estate and tax planning. Not all agreed on exactly what was in store, but one clear consensus emerged: secrecy is virtually dead as a wealth planning tool, offering a huge opportunity for practitioners and advisers who can grasp it.

Why? So long as some practitioners could rely on secrecy, estate planning was relatively easy for them in technical terms, said our respondents. With the distorting effects of secrecy wiped out, the task is going to be much more demanding. This is especially true as tax compliance will have to be achieved across many jurisdictions, not just where the client invests, but back home as well, or indeed anywhere the client might be exposed.

In short, the industry's future is in global tax advice. Naturally, complex cross-border wealth structuring requires a much higher quality of advice, and a bigger toolbox than the traditional trust. Practitioners must learn to structure in novel ways, while diversifying into products such as insurance, partnerships and foundations. As one of our respondents said, "All the products are there; it's not necessary to invent a new vehicle."

That wider expertise will bring with it a windfall for the skilled adviser, in the form of price premiums. Trusts, which have become to some extent commoditised through banks' cross-selling practices, will be priced at their true cost instead of being used as a loss leader.

STEP has christened this premium the "Transparency Dividend". It is true that many firms will have to lay out significant costs to reap the rewards, but most of our respondents reckoned the long-run returns will be worth it - probably within two to three years. In any case, they recognise they have little choice in the matter!

There is likely to be plenty of private client business to fight for. Precisely because of the economic downturn, onshore tax rates are more likely to go up than down in the coming years - especially for high net worth clients, many of whose trust portfolios have recently suffered severe financial losses.

This will drive wealthy families to seek out permanently low tax jurisdictions for their residence and their assets, respondents believed. Add to this the fact that non-compliant clients and families will have to migrate their affairs toward compliance, and it is clear that a lot of them are going to be looking for competent and innovative advisors and trustees.

Respondents to our survey also predicted that most IFCs would stay committed to the business - although some large banks with offshore private client trust branches may tend to put their onshore interests first.

There were suggestions that the new transparency may drive some IFCs away from the private client sector in favour of corporate work. The extent to which an IFC can be expected to support their private client sector is probably linked to their reliance on secrecy as a business practice.

But question marks remain over some jurisdictions where tax compliance has not been the norm and which are thus holding a weaker hand, said some of our respondents. Many predicted a shift of business from one centre to another.

The upshot may be a fight for survival for these IFCs. Not all will succeed. Some practitioners even welcomed the end of secrecy as likely to eliminate some of the less reputable players.

Meanwhile, the effect on some of the well-established and respected offshore jurisdictions will be to wake up those who have "fallen asleep at the wheel" as one of our panel put it. The relative ease of leaving assets undeclared may have made trust practitioners in these jurisdictions rather lazy; in future they will have to be much more creative if they wish to compete with the big onshore centres.

Most practitioners in these jurisdictions will probably advise client beneficiaries of legacy trusts either to fully disclose their assets to their home jurisdiction, or to migrate them to compliant structures over a period of time.

Others may choose to edge away from clients in the compliance-heavy Western economies. They may instead seek new business in easier hunting grounds - either the fast-growing ranks of high net worth Asian families, or in emerging economies which do not impose rigorous offshore disclosure demands on their citizens. However, this strategy has its drawbacks: it is much harder to capture a new income stream than retain an existing one.

Thus a limited number of practitioners in a few jurisdictions will doubtless continue to use secrecy for tax planning purposes, while the wider industry will increasingly repudiate it as being too closely linked to undeclared assets.

The question then arises: how can legitimate desires for confidentiality be protected in the new open environment?