Police are still at the scene of a crash involving a motorcyclist and car that happened just before 9am today (Friday).
A blue Honda motorbike was in collision with a white Ford Fiesta Zetec on the A4147 (Link Road) between Piccotts End Road and Cambrian Way.
The motorcycle was travelling eastbound whilst the Ford was travelling westbound.
The motorcyclist, a man in his 30s, has been airlifted to the Royal London hospital. He is in a serious condition.
The driver of the Ford, a woman in her 20s, has been taken to Watford General Hospital for treatment.
A spokesman for the East of England Ambulance Service Trust said an air ambulance had been scrambled to the scene along with two ambulance crews, a rapid response team and an ambulance officer.
It is believed the male motorcyclist has serious injuries to his pelvis, leg, arm and head.
The road remains closed at this time as the investigation into the incident continues.
Officers have asked motorists to avoid the area while police carry out an investigation into the incident.
Anyone who witnessed the collision, or saw the vehicles prior to it, should contact collision investigator PC Bob Hauxwell at the Bedfordshire, Cambridgeshire and Hertfordshire Forensic Collision Investigation Unit via 01438 757 500.