Longevity risk – or the prospect that you will live longer than you anticipate and therefore run out of retirement savings – keeps many people up at night.

Take actuary David Orford, the managing director of annuities business Optimum Pensions, whose mother died of a heart attack at 72. Her father also died of a heart attack at 72. Orford, 62, has had a heart bypass operation and takes cholesterol medication and reckons it is possible he will live longer than his father who died at 93.