Far from the ocean waves, past churches and fields, surfers ride the swell of the Severn Bore, one of Britain’s few truly spectacular natural phenomena.

Tidal bores are high, often dangerous, waves formed as incoming tides filter into a narrow channel, increasing the height of the water. The power of the surge is clear in these pictures, taken yesterday near the village of Hempsted, south of Gloucester, where surfers met for three of the biggest bores in recent years.