Tom O'Brien was a jockey. British and Irish racing communities mourn his death at 39 after a cancer diagnosis. Many publications called him a fantastic person. O'Brien secured victories at the renowned racing event. The Guardian and 7NEWS reported his death after a courageous fight with cancer. At Bangor, a colleague called him a champion and a skilled jockey. Yahoo News Australia said O'Brien was the second jockey to die in two days. Tributes continue in the world of horse racing.