Giorgia Bronzini (Wiggle-Honda) came in for second, with Lucy Garner (Great Britain) putting in a strong sprint to place third.
Former world time trial champion Emma Pooley (Lotto-Belisol) illuminated the stage. She initially attacked after 23 kilometres, shortly after Strava Queen of the Mountains leader Sharon Laws (UnitedHealthcare) extended her lead in the competition by finishing second atop Post Hill.
She was joined by a handful of others, before the peloton caught them after 40 kilometres. Pooley then attacked just before the feed zone at Buntingford. She was joined by Chantal Blaak, Janel Holcomb, Annemiek van Vleuten, Gracie Elvin and Katarzyna Pawłowska. The presence of the latter three was crucial - they respectively ride for Rabo-Liv, Orica-AIS and Boels-Dolmans, the teams of Vos, Emma Johansson and Lizzie Armitstead.
That left Astana-BePink and Wiggle-Honda to chase. The leaders gained a maximum advantage of approximately 50 seconds, before they were caught as the stage was neutralised as a result of a non-race-related road traffic accident on the course within 20km of the finish.
Racing resumed with 15km to go and with the peloton all together - and an inevitable bunch sprint on the cards.
Lizzie Armitstead (Boels-Dolmans) again suffered a mishap on the run-in to the line, requiring a spare bike after puncturing with 4km to go.
Vos's class shone through as she sped over the finish line, arm aloft and resplendent in the yellow jersey a good bike length clear of Bronzini. Armitstead made it back into the peloton in time for the finish, and admitted she "dive-bombed" the final corner in an attempt to contest the sprint. She finished 10th.
However, given the 10-second bonus she took on the line, few would now bet against Vos maintaining the lead when the race concludes on Sunday.
It was a mixed day for local sisters Laura and Emma Trott. Laura crashed heavily the previous day, but managed to start in her hometown of Cheshunt after getting the all-clear from medics. Emma, meanwhile, announced on the finish line that she will retire from the sport after Sunday's stage.
The final stage runs from Harwich to Bury St Edmunds over 108.3km.
Friends Life Women’s Tour 2014, stage four: Cheshunt to Welwyn Garden City, 97.8km
1. Marianne Vos (Ned) Rabo-Liv in 2-13-09
2. Giorgia Bronzini (Ita) Wiggle-Honda
3. Lucy Garner (GBr) Great Britain
4. Emma Johansson (Swe) Orica-AIS
5. Elena Cecchini (Ita) Estadio de Mexico-Faren
6. Lauren Hall (USA) Optum p/b Kelly Benefit Strategies
7. Leah Kirchmann (Can) Optum p/b Kelly Benefit Strategies
8. Aude Biannic (Fra) Liontek
9. Trixi Worrack (Ger) Specialized-Lululemon
10. Lizzie Armitstead (GBr) Boels-Dolmans all at st.
Overall classification after stage four
1. Marianne Vos (Ned) Rabo-Liv in 9-54-10
2. Emma Johansson (Swe) Orica-AIS at 0-19
3. Rossella Ratto (Ita) Estadio de Mexico-Faren at 0-22
4. Lizzie Armitstead (GBr) Boels-Dolmans at 0-30
5. Giorgia Bronzini (Ita) Wiggle-Honda at 0-31
6. Susanna Zorzi (Ita) Astana-BePink at st
7. Lucy Garner (GBr) Great Britain at 0-37
8. Hannah Barnes (GBr) UnitedHealthcare at st
9. Elena Cecchini (Its) Estadio de Mexico-Faren at 0-41
10. Amy Pieters (Ned) Netherlands at st.
Yodel Direct Sprints Competition
1. Marianne Vos (Ned) Rabo-Liv
Strava QoM Competition
1. Sharon Laws (GBr) UnitedHealthcare
Matrix Young Rider Competition
1. Rossella Ratto (Ita) Estado de Mexico-Faren
Stage win and overall lead for Marianne Vos as the Friends Life Women's Tour hits Clacton-on-Sea
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Nick Bull is an NCTJ qualified journalist who has written for a range of titles, as well as being a freelance writer at Beat Media Group, which provides reports for the PA Media wire which is circulated to the likes of the BBC and Eurosport. His work at Cycling Weekly predominantly dealt with professional cycling, and he now holds a role as PR & Digital Manager at SweetSpot Group, which organises the Tour of Britain.
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