A Norwegian man has been arrested after he was caught having sex with his girlfriend while speeding down a motorway.

Officers were following the car - which was swerving from side to side and travelling 20mph over the speed limit - when they noticed a woman "sitting on the man's lap".

After filming the act for evidence, police pulled the car over just outside the capital, Oslo.

The 28-year-old man is expected to face a fine of several thousand Norwegian kroner and an extended driving ban.

The man's 21-year-old lover was allowed to drive him home by police.