Traders in London were left in limbo today after Hurricane Sandy forced Wall Street to shut down for the first time since the September 11 attacks.

Investors struggled to find direction after it was confirmed that America’s two biggest trading platforms - the New York Stock Exchange and the Nasdaq Stock Market - will not open as scheduled at 1.30pm GMT.

The markets - home to some of the world’s biggest companies including Apple, Microsoft and Starbucks - also look set to be closed tomorrow, while commentators fear the suspension could run into Wednesday.

Michael Hewson, senior UK market analyst at CMC Markets, said the biggest impact of the shutdown in the US was likely to be a drop in trading volumes - an indicator of a lack of certainty among investors.

He added that amid concerns about the wider global economy, the US shutdown was “yet another reason for traders to remain on the back foot”.

Insurers came under pressure with the likes of Hiscox, Amlin and Catlin - major underwriters for the whole industry - falling on the FTSE 250 Index amid fears the approaching superstorm would cause billions of US dollars of damage.

The FTSE 100 Index was more than 0.5% lower.

The New York Stock Exchange initially said it would only close the market floor but continue using electronic trading - but this was later changed to cover all forms of trading.