Police closed the A1 north and south-bound for an Air Ambulance to land, after a road traffic collision on the north side at Long Bennington.
According to a police spokeswoman the accident involved a silver Vauxhall which hit the central reservation from the north side and came to a stop upside down.
They confirmed that one person was taken to hospital by road ambulance and another by Air Ambulance, with both carriageways closed while this landed.
Delays are expected while recovery of the Vauxhall from the north-bound carriageway takes place, with no other vehicles said to be involved.
The Highways Agency say one lane is closed north-bound between the A52 and A46, with delays of 40 minutes and normal traffic conditions expected from 6.00pm.