The pre-race favourite, Armitstead spent much of the 129.8km race back in the pack but, with just a kilometre left, powered to the front and then timed her move perfectly as she added the rainbow jersey to her overall World Cup title.
The 26-year-old becomes the fourth British woman to be crowned road world champion, joining Nicole Cooke, Mandy Jones and Beryl Burton.
Dutchwoman van der Breggen, runner-up in the women's time trial, settled for silver again while American Megan Guarnier took third.
"Every cyclist dreams of the rainbow jersey," Armitstead told reporters. "This morning I had never been so nervous in my life. That's why I am still in shock really. It just went so perfectly. It is one of those things you dream about in your career.
"I prepared the best I could. Physically I was in the best shape of my career and then you have to have lady luck on your side and she was with me today.
"Even rain, it was perfect."
Armitstead's hopes of victory appeared doomed when she failed to join a nine rider break that opened up a minute advantage on the peloton with under 20km to go.
But on the final climb up the Libby Hill cobblestones the leading pack was caught and then the bunch chased down Australian Lauren Kitchen and Italy's Valentina Scandolara, who had tried attacking alone.
With the race now set up for a sprint finish, a cool Armitstead held her nerve on the finishing straight, slowed the pace and waited for someone to make the first move.
Van der Breggen seized the chance but Armitstead responded immediately and powered to a half-bike length victory over the Dutchwoman.
"With about a lap to go I put in a little dig over one of the cobble climbs. I thought this could be over if we don't bridge across," said Armitstead.
"I was hoping at that point someone would come across with me to the breakaway but I kind of put myself away on my own and I wasn't prepared to chase on my own.
"So it was a case of willing to lose the race in order to win it. I knew that from last year I had to be patient, I had to gamble.
"Until we caught them I thought it was over."
The race, run over 16 circuits, set a torrid pace and featured numerous solo attacks and counter-attacks with Russian and Australian riders initiating much of the action.
With 24km to go Australian Rachel Neylan made a bold solo break but was soon joined by eight others, setting up the breakaway that nearly stole the race.
"I had good legs, I was getting quite frustrated by the racing really, when was it going to happen?" said Armitstead.
"The peloton was going slower and slower each lap so I think the course was quite demanding and then last five kilometres were challenging and it was all about positioning."
(Editing by Mark Lamport-Stokes/Andrew Both)
Share
