Michael Lewis has shown how tech nerds rigged the stock markets. But who will guard the geeks?

Light travels at 186,000 miles a second in a vacuum, which is another way of saying that it covers 186 miles in a milli-second - a thousandth of a second. Given that much of our contemporary electronic communications are conveyed by pulses of light travelling along fibreoptic cables, we are given to extravagant hyperbole about the "death of distance".