Investors who took the adventurous leap into so-called emerging markets have had an even nervier week than those who stayed in the better-known markets. Hong Kong's collapse has been well trumpeted, of course. But other east European and African equity markets also took a pounding. Among the markets which have suffered are all the Russian markets the stockmarket there fell 25 per cent on Tuesday alone. South American markets were also hit heavily in the initial sell-off.

Some investors will no doubt decide to take their profits on shares which are still up 40 per cent to 50 per cent on the year.