Isle of Man TT racer Seamus Greene was today fighting for his life after the Donegal man collided with a competitor during practice.
The crash also involved Japanese rider Jun Maeda, with Greene's condition described as "critical" after he suffered head injuries.
Maeda sustained pelvic injuries descried as "serious", although he was conscious.
With practice barely underway, the riders had collided coming out of the Union Mills section of the 33.73-mile Mountain Course which follows shortly after the start-finish line in Douglas.
After the TT newcomers - riders in their first year at the festival - had set off on an obligatory first lap escorted by travelling marshals, the 38-year-old Maeda had been the first of the experienced riders to begin his practice before being followed by Greene.
The session, which was scheduled to run for one hour and 40 minutes, was immediately halted following the incident.
A TT spokesman said: "There was a two-bike incident coming out of Union Mills on the way to Glen Vine section.
"The riders involved were Jun Maeda and Seamus Greene, who were in collision, and both have been taken to hospital by helicopter.
"The road was swept of debris, fuel and so on prior to the solo practice session restarting at 7.45pm."
The Maeda-Greene collision follows the crash on Saturday evening of sidecar crew Doug Dano and James Cornell.
