The new technology allows the company to fix joints on large iron gas mains without digging multiple holes in the road.
The Cisbot, developed by New York firm ULC Pipeline Robotics, can carry out repairs while the gas is still flowing, so the pipe does not need to be taken out of service.
The first live test took place outside Woolwich Barracks in south London, where the robot sealed a joint in a 24-inch gas main.
Paul Denniff, network director at SGN, said the use of technology was part of a commitment to “transform the way we work in the street”.
SGN innovation and new technology manager Gus McIntosh said: “We’re hugely excited about being the first distribution network in the UK to successfully seal a lead yarn joint on a live gas main, using this robotics system.”