The motorcyclist injured in an accident on Bradford Road in Brighouse yesterday has been moved to a hospital in Sheffield.
The biker - a 47-year-old man thought to be from Bailiff Bridge - was initially taken to Huddersfield Royal Infirmary after the collision involving his bike and a car at the junction of Woodvale Road, outside Brighouse Leisure Centre, at around 7am.
It is thought he suffered head, shoulder and pelvis injuries.
His condition has today been described as serious.
The road was closed for six hours and diversions were put in place while emergency services dealt with the accident.
Police are appealing for any witnesses to contact them via 101.