Junior Heffernan, 23, was riding the second lap of the 66-mile Severn Bridge Road Race in South Gloucestershire when he collided with a vehicle at high speed. He died as a result of his injuries, Cycling News reported.
Officials have yet to release official details of the crash, but witnesses said Heffernan was trying to pass the peloton -- the pack of riders -- when the accident occurred.
The Severn Bridge race was the first in which "The Heff" was riding with his new team, Team Herbalife-Leisure Lakes. Officials called off the 10-lap race after the crash.
"This is a tragedy which will profoundly sadden everyone associated with cycling in this country," said British Cycling president Brian Cookson. "My thoughts are with Junior's family and with his friends."