Biography

His son, Jim Sullivan has joined him as a comedy writer.

When he wrote the Only Fools and Horses (1981) episode Strained Relations that dealt with Grandad's death, it was a watershed episode because it was the first time a sitcom had ever directly tackled the topic of death, which had always been a touchy subject for sitcoms in the past. But he didn't want Lennard's Pearce's death to go unacknowledged by the BBC.

Before the sixth series of Only Fools and Horses (1981), David Jason was annoyed about something and went to see Sullivan. Sullivan was writing terrific scripts that were too long and had to be edited down to 30 minutes. Jason felt they were cutting more funny material than most sitcoms manage in a full episode. One edit that had particularly vexed Jason was during the Series 5 episode Tea For Three. After Del Boy returned from a disastrous hang-gliding session, he originally had a speech Jason described as "beautifully constructed, full of suppressed rage" about all of the places Del had visited. Jason considered it a comic masterpiece, but because the episode had overrun, half the speech got cut. Sullivan agreed with Jason that the episodes needed to be longer. Jason and Sullivan approached Gareth Gwenlan while he was producing Series 6 with the plan to extend the episodes from 30 to 50 minutes. Gwenlan didn't think that was possible since sitcoms were traditionally 30 minutes in length, and couldn't sustain a longer running time. Jason said that would be true of an average writer, but not one of Sullivan's caliber. And yet they still keep cutting great material. Gwenlan than okayed the idea.

He felt David Jason was wrong for the part of Del Boy; he envisioned Del a winner, whereas Jason was known for playing life's losers, but later changed his mind after the read-through for the pilot episode. The BBC also felt Jason was wrong because he and Nicholas Lyndhurst looked nothing alike; Sullivan disagreed. Del needed to be shorter to remove any sense of physical intimidation between the brothers, and to imply the suspected illegitimacy of the Trotters.

Sullivan and Gareth Gwenlan approached David Jason in 2011 with Del Boy coming back at 65 and what had become of everyone from Only Fools and Horses (1981). Jason was up for it because anything was possible in Sullivan's hands. But two weeks later, Gwenlan phoned Jason saying Sullivan was in intensive care with viral pneumonia. He seemed on the mend, and got to leave hospital and go home at one point, but he had a relapse and went back to hospital and died not long after.