It has been nine years in gestation and today it takes effect. But implementation day for Mifid - the markets in financial instruments directive - will not be a Big Bang event in the creation of the European Union's single financial market so much as the start of a long roll-out.

One reason is that, at the last count, 10 of the EU's 27 member states were still unprepared for Mifid despite having had an extra 18 months for governments to dot the 'i's and cross the 't's of the new legislation and for companies to put the necessary investments in place.