Barely a ripple disturbs the lake sprawled outside the window of my stone cottage. Sunlight bathes its pale bed and spangles its surface – a tie-dye of piercing blue on the horizon, turquoise on the fringes and translucence in the rock pools, where submerged stones are cast into pin-sharp focus. The air is warm and thick with tranquillity.

Sometimes, when the mwera (trade winds) funnel from the south-east up this stretch of the waterlogged Rift Valley – Africa’s third-largest lake – the palm trees twist and shake and the lake’s surface buckles. Then surfers paddle out on their boards and catch freshwater waves back to shore.