The hardest road climb in England? #55 Rosedale Chimney North York Moors by MuddyGoose - September 16, 20154 It's not the longest climb, it's not the climb boasting the greatest elevation gain either and it's also not the climb at the highest altitude but. I'm tempted just to leave it at that; just a lingering 'but'. If Rosedale Chimney isn't the steepest climb in the UK then it's pretty well close to it! 413