UTC, who will play as Perpignan in Super League XI, held off a Broncos fightback to record a famous 28-24 win in this pre-season friendly.
In a closely-contested match both sides ran in five tries in front a raucously partizan crowd of 3,000 in southern France.
UTC led 22-4 early in the second half before the Broncos battled back and almost seized a victory.
Winger John Kirkpatrick scored two tries for London, the other tries coming from three new signings - Lee Hopkins, Solomon Haumono and Nick Bradley-Qalilawa.
UTC are set to join the Super League as Perpignan for the 2006 season. Next up for London as they prepare for the start of Super League X is a friendly against champions Leeds Rhinos at Headingley on Tuesday.Like