Although the defending champion, Nick Craig, pedalled to a lone lead of 17 seconds with 4.4km to race, Knight's running ability brought him level on the final 2.2km lap.
Then on three climbs, where riders needed to dismount and carry their bikes, Knight sprinted clear to win by 14 seconds from Craig, with Barrie Clarke third.
The new champion said: "It is unbelievable because my form has dipped over the last few weeks. When I realised that the course would be frozen hard I knew that it could be my day."
Apart from his title, Knight also won selection for the World Championships in Slovakia at the end of this month, and earned 100 points that will lift him into the top 40 in the world rankings.
Knight's world team-mates will be Clarke, from Epsom, Stuart Blunt (Sutton, Surrey), Matt Ellis (Stockport) and Richard Thackray (Bradford).Reuse content