Scunthorpe's two-year stay in the Championship ended in dismal fashion as Nottingham Forest virtually sealed a play-off spot with a crushing victory.
The Iron needed to win to stand any chance of surviving but made the worst possible start when Kris Boyd put Forest ahead after only nine minutes.
Luke Chambers extended the lead before Michael O'Connor halved the deficit from the penalty spot.
But goals from Paul Anderson, Chambers and Boyd completed the rout.
Scunthorpe will return to League One next season, while Forest look near certainties for an appearance in the play-offs for the second season running.
Billy Davies' side will go into the final game three points in front of seventh-placed Leeds but six goals better off on goal difference.
Scunthorpe started brightly and Mark Duffy forced Lee Camp to parry a shot from the left side of the box after seven minutes, but Boyd opened the scoring shortly after with a low 12-yard effort.
Joe Murphy kept Scunthorpe in the game with two saves in quick succession to deny Robert Earnshaw and Chris Gunter.
However, there was little Murphy could do to prevent his side from falling 2-0 behind after 25 minutes when Chambers headed home from close range from Chris Cohen's corner.
Despite such a huge setback to their survival hopes, the visitors persevered and Camp tipped a 25-yard effort from Ramon Nunez over the crossbar before blocking a Grant shot.
Scunthorpe's endeavour was rewarded nine minutes before the break when Gunter brought down Nunez and O'Connor emphatically dispatched the penalty into the top corner.
Lee Miller then replaced the injured Chris Dagnall but the change did not affect Scunthorpe's rhythm and O'Connor worked Camp again with a fiercely struck free-kick that the Northern Ireland international had to push away.
Forest made two substitutions of their own at half-time, with Anderson and Guy Moussi coming on for David McGoldrick and Paul McKenna in a tactical switch by Davies.
It proved to be a master stroke as Anderson smashed home Lewis McGugan's free-kick from close range in the 48th minute.
The goal seemed to drain the life out of Alan Knill's team, who created little after Nunez had speculatively shot wide from long range after 53 minutes.
Forest too appeared to have less urgency, apart from a curling Earnshaw effort after 70 minutes from the right side of the box that Murphy pushed away.
The game meandered until eight minutes from time when Chambers headed his second goal of the game from another Cohen cross.
On-loan Middlesbrough striker Boyd then netted his six Forest goal and his 12th of the season with a superb 25-yard free-kick in the final minute.