Mary King is a sportswoman like few others.

She's 50-years-old and still at the pinnacle of her sport.

That sport is three-day eventing.

Next year, she's hoping to collect her first Olympic gold medal - at what will be her sixth games.

But is equestrianism - as its enthusiasts insist - the toughest sport in the world?

Or is it less a test of the person - more of the horse - and a preserve of the rich?

(Image: Mary King. Credit: Press Association)