Fumio Kishida criticises actions of eldest son, Shotaro, after photos show him lying on the stairs and posing at a press conference podium

The eldest son of Fumio Kishida, the Japanese prime minister, is to step down as his executive policy secretary amid public outcry over his use of the leader’s official residence for a private party.

Photos published by the Shukan Bunshun weekly magazine showed his son Shotaro and about 10 relatives posing or lying on the symbolically important red-carpeted stairs of the residence in an imitation of group photos of newly appointed cabinets. Shotaro is at the centre – the position reserved for the prime minister.