COVENTRY have been relegated to League Two after drawing 1-1 at home to Charlton in a match delayed by both teams' supporters throwing plastic pigs onto the pitch to protest against their owners.
Kick-off was postponed by 15 minutes after the disruption which, as with the reverse fixture at The Valley earlier this season, was preceded by further demonstrations against Coventry's owners Sisu and Charlton's, Roland Duchatelet, outside the Ricoh Arena.
George Thomas gave the hosts hope of victory with his first-half finish, but Charlton's Patrick Bauer equalised during the second half to ensure Coventry's relegation.
Chesterfield were nudged closer to relegation after losing 4-0 at home to play-off hopefuls Southend.
They were already 1-0 down, through Simon Cox's goal, when Dion Donohue was sent off and thereafter fell further behind with Cox's second goal and finishes from Anthony Wordsworth and Marc-Antoine Fortune.
They are nine points from safety with three remaining fixtures and their goal difference of -31 is 17 worse than Bury in the final survival spot.
Southend remain in seventh, just outside of the play-offs, after Millwall stayed sixth with a 3-0 defeat of Northampton. Two goals from Jed Wallace and another from Aiden O'Brien secured victory.
Fleetwood, who are third, maintained their hopes of automatic promotion by winning 2-1 at Peterborough. Bobby Grant and Ashley Eastham scored first-half goals before Craig Mackail-Smith replied for the hosts.
Fourth-placed Bradford also strengthened their prospects with a 1-0 win over Oxford, courtesy of Nicky Law's goal, to stay level on points with Fleetwood and move four behind Bolton, who play on Saturday.
Scunthorpe's 1-0 win at MK Dons keeps them two points further back in fifth. Ivan Toney scored the game's only goal.
Port Vale's survival hopes worsened in the absence of victory. Vale lost 3-0 at home to champions Sheffield United. Jay O'Shea, Leon Clarke and Matt Done scored the goals.
Fellow relegation candidates Shrewsbury remain 19th after drawing 1-1 at home to Walsall. Kieron Morris headed the visitors in front before Stefan Payne's equaliser.
Gillingham moved closer to survival with a 3-1 defeat of Bristol Rovers that left them 17th. Cody McDonald secured victory with two late goals after Rovers' Billy Bodin cancelled out Josh Wright's opener.