Nick Goodway: Could the Greeks be indebted to IT as clocks go back by a second?

What do you plan to do with your extra second tonight?

If you were unaware, the clocks will actually tick back one second at midnight GMT. So if you are watching a truly digital timepiece, it should go 23:59:59, 23:59:60 and then 00:00:00.

This occurs quite regularly. In fact, it has happened no fewer than 25 times since 1972.

The last occasion was in 2012 when a handful of things such as the Qantas website and LinkedIn fell over.

But tonight will be the first time since financial markets went almost entirely electronic that the extra second is being inserted during a trading day.

The potential for chaos is huge. So huge that some markets in the US will be closing early and others will delay trading.

Given that electronic trades these days can be put through at rates of 80,000 per second and the vast majority of those are done by computers not humans, there is plenty of room for error.

Banks and brokers say they have been preparing for the extra second for many months. IT firms are quietly confident that their systems will remain upright.