Now the schools' 470 sixth formers, who already shared some courses, commute cheerfully between lessons in taxis and enjoy the benefits of about 30 A-level courses. They also have a choice of five General National Vocational Qualifications (GNVQs) - far more than any single school could offer.
Competition for 11-year-olds has also been eliminated, with each school recruiting only in a predetermined catchment area. Parents are free to choose a school outside their area, but its head will gently point out that their home school is also a very good one.
Staff are happy to share sensitive information on budgets and planning, and exam results are published through a joint statement so there is no question of one school proclaiming victory over the others.
Sitting in the headteacher's comfortable study at the King Edward VI School, the town's former boys' grammar school, the four headteachers agree that this small market town could easily have been the scene of a battle to the death. Instead, there is a strong sense of camaraderie, and all confess that they feel happier for knowing there are others with whom they can share their professional worries.
Don Willcox of the Elizabethan High School, the former girls' high school, explains: "There is a healthy rivalry between schools. We are not living in an unreal world. But there is a higher responsibility that we have, as a group of people, to the community."
In this way all four schools have remained viable, though three still have surplus places. In addition, the staying-on rate in the town has risen from 13 to 65 per cent.
With the new GNVQ courses, the head teachers say they can keep pupils at school who would have been lost to the system in the past. In some cases, the pupils choose to go to a further education college (there is still competition from that quarter, but the schools are hoping to forge closer links with the nearest college soon) but most stay at school.
One success story is Rachel Marriott, who was interviewed at several colleges before staying on at King Edward VI to take an intermediate-level GNVQ in Leisure and Tourism offered by Tuxford. A year later, she is now on an advanced course in the same subject at Elizabethan High School, but still attends her "home' school for core skills lessons.
Her mother, Val, says: "Rachel has done better than anyone expected. It's the best thing that could have happened to her."Reuse content