Robert Plummer writes at the BBC:

Ultra-fast trading has transformed global markets in recent years, but regulators have been accused of an ultra-slow response to changing times.

Thanks to complex computer software and algorithmic formulae, it is now possible for stocks, shares, currencies and commodities to change hands in fractions of a second, without the need for human intervention.

In the financial centres of Europe and the US, where the practice began, the people responsible for policing the markets are getting worried about their ability to cope.

But while they talk about how to curb it, trading based on algorithms is not going away. In fact, it is spreading faster than ever, as emerging markets catch on to its potential.

"The Bric (Brazil, Russia, India and China) countries are where it's at right now," says Dr John Bates, executive vice-president and chief technology officer of Progress Software, a company that has pioneered new techniques in what are known as quantitative trading programs.

You might also be interested in some more of the BBC's coverage on this:

• Quant trading: How mathematicians rule the markets
• When algorithms control the world