The partnership will see the rebranding of the motoring sections of its newspaper companion sites under the motors.co.uk banner.
Trinity Mirror became the sole owner of the Fish4 brand, which also includes Fish4Jobs and Fish4Homes, after buying out Newsquest’s share last year.
However motors.co.uk has now become the dominant player in the motoring sector and already boasts partnerships with Archant, Iliffe News and Media, the Midland News Association and a number of smaller publishers.
Tom Harte, sales director of Trinity Mirror Regionals said: “Trinity Mirror is now able to offer consumers and dealers a powerful new search tool through our new partnership with motors.co.uk, one of the UK’s leading used car classified networks.
“Our readers, website visitors and dealers will benefit from this enhanced online search service which will better enable buyers to find the car of their choice, locally.”