Prof Mark Cannell holds the chair of cardiac cell biology at Bristol University UK. He has worked in New Zealand and in the USA and is internationally known for his pioneering work on calcium measurement in single cells. His co-discovery of microscopic calcium signalling events called “calcium sparks’ revolutionized our view of how cells can partition signals to achieve speed, high gain and fidelity. His work is also known for its use of mathematical modelling to test ideas about signalling as well as the development of high resolution optical techniques.