No matter how rapidly the human eye can blink, a computer trading system on Wall Street has already left it for dust – carrying out a transaction 1,000 times faster, at just 400 microseconds. It is a frenetic, technology-driven world of which few ordinary investors are even aware.

But this “high-frequency trading” is estimated to account for well over half of daily volume in US stocks, up from estimates of 30 per cent in 2005. It is based on extracting tiny slices of profit from trading small numbers of shares in companies, often between different trading platforms, with success relying on minimal variations in speed – or “l(fā)atency”, in the trading vernacular.

It amounts to a transformation in equity trading that has lowered dealing costs virtually all round and, many argue, has created a more efficient market for both retail and institutional investors.