Harvey Jones says investor Warren Buffett knows exactly how to respond to the latest FTSE 100 (INDEXFTSE: UKX) crash. : Last year was a dreadful one for the FTSE 100, which ended the year down 12%, and 2019 has started in a blaze of volatility. The index currently trades at 6,783, similar to levels seen two years ago, and could go anywhere from here. At times like these it pays to listen to the coolest investment head of all, US billionaire investor Warren Buffett, whose words of wisdom are always worth remembering in tough times.