On 30 December 1952, Gunter was on his normal bus route in a number 78 double-decker bus only a couple of weeks after the Great Smog of London had brought London to a standstill.
As Gunter approached Tower Bridge at a speed of 12 mph (19 kph), the light at the beginning of the bridge was green, the warning bell was not ringing, and the bridge gates were not closed, falsely indicating that it was safe to cross. As a result, the bus continued onto the bridge, approaching the edge of the south bascule as it started to rise.
At this point, Gunter made a split-second decision to accelerate the 7.5-ton (7,500 kg) double-decker bus over the 6 ft (1.8 m) gap instead of slowing down and potentially tumbling backwards. He managed to clear the gap and land on the north bascule which had not yet started to rise.
While there were no fatalities as a result of the jump, there was one major injury (the conductor broke his leg) and twelve minor injuries. The bus suspension was broken.[3]
Gunter was given a reward of £10 (£252.83 as of February 2026[4]) and a day off work for his bravery. When asked what he would do with the bonus, he said, "five for me and five for the missus".[5]
Gunter was later quoted saying, "I'd always wanted to jump the bus over the gap! And I got a day off and a tenner for it, to boot!"[2]
