The A2 was closed in both directions after a major accident near Dartford Heath earlier this morning.
The crash happened at around 9.20am near the junction with Old Bexley Lane.
A 30-year-old man has been taken to Queen Elizabeth Hospital in Woolwich with leg, chest and abdominal pains.
Kent-bound traffic has now been released after congestion was all the way back to the Black Prince Interchange.
- As it happened: all the action from Anthony Joshua's world title fight at The O2
- EU referendum results and reactions for SE London and north Kent - how did your borough vote?
- Former Queen Elizabeth Hospital gynaecologist guilty of series of sex assaults on patients
- Man, 26, arrested over burglary at Gravesend gurdwara
- David Cameron to RESIGN as Britain votes to leave European Union