Italian Katia Ragusa of LIV Racing was second and Fenix-Deceuninck rider Marthe Truyen of Germany was third as outsiders took the top six in a feared racing date known as the "Hell of the North".
Rain during the week combined with bright sunshine on the day made the road surfaces slick. EF rider Jackson was one of 18 outsiders who got away in an early escape that managed to stay ahead all the way home.
This was thanks to last year's champion Elisa Longo Borghini bringing down the entire group of favourites on one of 17 sections of the cobbled mining roads in northern France. "I could hardly believe it when I got across the line," said the 34-year-old, who dominated the sprint from beginning to end. "I'm going to use whatever force I have left to stagger up to that podium, I am so, so ready for this," said the exuberant Jackson.
Handed a huge cobble gleaned from the unused mining roads near the border with Belgium, Jackson cut an exultant figure hopping up and down as she laughed with nerves. "It's unreal, I'm lost for words.