From 1980 to 1988 he wrote in partnership with Alan Grant, an old friend and former D. C. Thomson and 2000 AD sub-editor with whom he was sharing an old farmhouse in Essex, although most stories were credited to Wagner alone (under one of his pseudonyms) or Grant alone – whichever of them typed the script up got the cheque.
Wagner (as John Howard or T. B. Grover) was credited with "Judge Dredd", and Grant with the less frequent "Robo-Hunter", "Strontium Dog", and the Judge Dredd spin-off "Anderson, Psi Division", while some strips, like the CB-inspired space haulage comedy "Ace Trucking Co.", were credited to "Grant/Grover". "
Judge Dredd" was credited to "Wagner/Grant" starting in 1986.

Other pseudonyms were created, at the insistence of publisher John Sanders, to disguise how prolific the two writers were.
For the revived Eagle they wrote "Doomlord", "Joe Soap", "Rebel the Police Dog", "Computer Warrior", "The Fists of Danny Pyke", "Manix" and "The House of Daemon"; for Scream!
they wrote "The Thirteenth Floor", for Roy of the Rovers they wrote "Dan Harker's War", and for Battle they wrote "Invasion 1984".
During this time Wagner wrote the documentary strip "Fight for the Falklands" for Battle, without Grant who had no interest in war stories, and "Dan Dare" with Pat Mills for Eagle.

Wagner and Grant became part of the so-called "British Invasion" of American comics during the 1980s.
In 1987 their first title, a mini-series called Outcasts, was published by DC Comics with Cam Kennedy as artist.
Outcasts was well received, though it never sold in great quantities, and this success led to the pair writing Batman in the pages of Detective Comics from issue 583, largely with Norm Breyfogle on art duties.
Grant and Wagner introduced the Ventriloquist in their first Batman story and the Ratcatcher in their third.
The pair also created the bleak nuclear dystopia The Last American for Epic Comics with longtime Dredd artist Mike McMahon.
Arguments over the direction of that title and the ending of the Judge Dredd story "Oz" led to the end of their writing partnership and they split their work between them: Wagner kept "Judge Dredd", while Grant continued "Strontium Dog" and "Anderson, Psi Division" and became the sole writer of Detective Comics.
Although the two continue to collaborate from time to time, they have never resumed a full-time partnership.
From 1980 to 1988 he wrote in partnership with Alan Grant, an old friend and former D. C. Thomson and 2000 AD sub-editor with whom he was sharing an old farmhouse in Essex, although most stories were credited to Wagner alone (under one of his pseudonyms) or Grant alone – whichever of them typed the script up got the cheque. Wagner (as John Howard or T. B. Grover) was credited with "Judge Dredd", and Grant with the less frequent "Robo-Hunter", "Strontium Dog", and the Judge Dredd spin-off "Anderson, Psi Division", while some strips, like the CB-inspired space haulage comedy "Ace Trucking Co.", were credited to "Grant/Grover". "Judge Dredd" was credited to "Wagner/Grant" starting in 1986.
Other pseudonyms were created, at the insistence of publisher John Sanders, to disguise how prolific the two writers were. For the revived Eagle they wrote "Doomlord", "Joe Soap", "Rebel the Police Dog", "Computer Warrior", "The Fists of Danny Pyke", "Manix" and "The House of Daemon"; for Scream! they wrote "The Thirteenth Floor", for Roy of the Rovers they wrote "Dan Harker's War", and for Battle they wrote "Invasion 1984". During this time Wagner wrote the documentary strip "Fight for the Falklands" for Battle, without Grant who had no interest in war stories, and "Dan Dare" with Pat Mills for Eagle.
Wagner and Grant became part of the so-called "British Invasion" of American comics during the 1980s. In 1987 their first title, a mini-series called Outcasts, was published by DC Comics with Cam Kennedy as artist. Outcasts was well received, though it never sold in great quantities, and this success led to the pair writing Batman in the pages of Detective Comics from issue 583, largely with Norm Breyfogle on art duties. Grant and Wagner introduced the Ventriloquist in their first Batman story and the Ratcatcher in their third. The pair also created the bleak nuclear dystopia The Last American for Epic Comics with longtime Dredd artist Mike McMahon. Arguments over the direction of that title and the ending of the Judge Dredd story "Oz" led to the end of their writing partnership and they split their work between them: Wagner kept "Judge Dredd", while Grant continued "Strontium Dog" and "Anderson, Psi Division" and became the sole writer of Detective Comics. Although the two continue to collaborate from time to time, they have never resumed a full-time partnership.
John Wagner