Crowds gathered in Flag Market to pay their respects to the father-of-four, who died from cancer on September 28, as the funeral cortege made a special visit to his famous Guild Tram outside the Harris Museum.
Hundreds of people clapped in unison as his coffin, adorned with white and red roses, passed by his much-loved food stall at 10.50am.
Family, friends and customers shared their fond memories of Mr Roberts, whose baked potatoes and traditional parched peas were a fixture of the city's Flag Market for decades.
A family friend, Stephen Geraghty, from Preston, said: “Everyone who knew Keith had amazing things to say about him.
"My brother was one of Keith’s best friends and I knew him through family. Everyone calls him a legend and he was in every sense a legend in Preston and loved by many.
Another family friend Karen Holland added: “We had been good friends with Keith for the best part of 31 years.
"His death is horrible, he was too young, but his legacy will live on.
"Hopefully, someone will take over that van and keep his famous hot potatoes going."
You can read our tribute to Keith Roberts here.