Police were called at about 8.45am following reports of an incident believed to have involved six vehicles on the southbound carriageway of A1. A spokesman for Cambridgeshire police said: The collision involved a Citroen Relay, Citroen DS4, Ford Focus and two Honda Civics. It is believed a sixth vehicle was also involved, but the details of this are not available at this time. No injuries were reported as a result of the collision. The road was initially closed from B645\/B1048 at Eaton Ford, but one lane has now re-opened. There are lengthy delays in the area while traffic begins to flow again. Anyone who witnessed the collision is asked to call the road policing unit on 101.