Police were called to the collision near Roundswell at around 11am. A man was airlifted to Derriford Hospital as a result of the accident. Police said his condition is critical but stable. The A39 has been closed in both directions between Roundswell roundabout and the Instow turn-off. It is expected to be closed until early evening while collision investigators are on the scene. Diversions are in place along the B3233, although traffic is slow. Stagecoach South West said its services across North Devon were suffering with 'extreme delays' as a result. A tweet from the company said: "Barnstaple services across North Devon suffering with extreme delays due to A39 North Devon Link Road closure. "All traffic is diverted via Fremington causing services to operate up to 45 minutes. Sorry for any inconvenience."