He is now also a commentator/pundit and TV personality. He is also referred to by the nickname Billy Whizz after the character in British comic The Beano.
In April 2017, he was critically injured after being involved in a collision at Donington Park that caused both of his legs to be amputated, one below the knee and the other above the knee. Until that, he had been heavily involved in kart racing all over the UK and the Channel Islands and then a successful Ginetta Junior racer.
After treatment and therapy, Monger returned to competition in November 2017. In 2018, Monger was awarded the BBC Sports Personality of the Year Helen Rollason Award for outstanding achievement in the face of adversity. From 2019, he supplied analysis for Channel 4 F1. He also competed in the Formula 3 based Euroformula Open championship for Carlin Motorsport, achieving his first single seater race win at the 2019 Pau Grand Prix.