A car has overturned between J7 Kettering North and J8 Kettering Central on the A14.
Emergency services are on the scene but traffic is backed-up as far as junction 3, with slow-moving vehicles also on the opposite carriageway.
It is expected to be at least an hour before the accident is clear.
Traffic is at a standstill and delays are timed at about 20 minutes.
The extent of any injuries is unknown.