Hardtalk speaks to the most successful Olympic sailor of all time - British four-time gold medallist Sir Ben Ainslie. In September he was part of team USA which enjoyed a spectacular victory against team New Zealand at the America's Cup in San Francisco. But sailing is becoming more and more expensive - with critics saying it is now a niche sport funded by billionaires and enjoyed by the few. How can its appeal be broadened?(Photo: Sir Ben Ainslie)