Alejandro Valverde is aiming to retain his road race crown at the UCI Road World Championships ©Getty Images

The 2019 International Cycling Union (UCI) Road World Championships start tomorrow in Yorkshire, the first time Britain has hosted the event since 1982.

The newly formatted team time trial commences the competition, and will be raced as a mixed-gender relay.

Consisting of three men and three women in national teams, riders take on two laps of a tricky town centre circuit in Harrogate.

Individual time trials take place for men, women and juniors during the week, along with the junior road races, before the senior road race champions are crowned next weekend.

The men's road race on September 29 closely follows the 2014 Tour de France Grand Départ stage, starting in Leeds, winding through the Dales before reaching Harrogate, where competitors must then do an added seven laps of a 14 kilometre circuit in the spa town on a gruelling course of 284.5km overall.

Dutch rider Anna van der Breggen is defending the women's road race crown ©Getty Images
Dutch rider Anna van der Breggen is defending the women's road race crown ©Getty Images

The women's race the day before is a challenging 149km course, with tough climbs and three circuits in Harrogate.

The men's time trial is a 54km race from Northallerton to Harrogate, while the women will compete over a 32km course.

The reigning champion in the men's road race is Spaniard Alejandro Valverde, who ended Slovakian Peter Sagan's three-year dominance.

Mathieu van der Poel of The Netherlands is among the favourites after winning the Tour of Britain, while Julian Alaphilippe – who came so close to home Tour de France glory – is also in contention.

Dutch rider Anna van der Breggen is defending the women's crown.

Rohan Dennis of Australia and Dutchwoman Annemiek van Vleuten are aiming to retain their time trial titles.