Police and paramedics are helping a motorcyclist who has come off his bike on a Watford road shortly after 9am.
Ambulance crews are attending to the biker - a man in his 50s - who has suffered a leg injury in Upton Road.
Richard Dunne, spokesman for the East of England Ambulance Service, said: "We were called at 9.15am. An ambulance is still there.
"A motorcyclist came off his bike. It was a man in his 50s. He has an injury to his lower leg."