Hearts have launched legal action against the Scottish Professional Football League after a final failed attempt at reconstruction consigned them to a shortened season in the Scottish Championship.
The SPFL board "agreed to draw a line under reconstruction talks" after only 16 of the 42 clubs backed plans for a 14-10-10-10 set-up in an informal vote.
It was also confirmed Championship clubs had approved a reduced 27-game campaign, which is scheduled to kick off on October 17.
The vote ratified relegation for Hearts, Partick Thistle and Stranraer, who were bottom of their respective divisions when the coronavirus pandemic halted the campaign.
Clubs voted to terminate the season and decide placings on a points-per-game basis but Hearts - who were four points adrift -are not prepared to accept their fate.
A club statement read: "This was the final opportunity for kinship to prevail and for Scottish football to stand together in an emergency. It is an unfortunate condemnation of Scottish football that this was not possible.
"Now that all other avenues are closed, we are left with no choice but to proceed with a legal challenge. The club has tried throughout these last few months to avoid this course of action but we must now do the right thing by our supporters, our employees, our players and our sponsors.
"We can hold our heads up high as we have acted at all times with integrity, common sense and with the best interests of Scottish football at heart.
"We have stated from the beginning that the unjust and unfair treatment of Hearts, Partick Thistle, Stranraer and indeed other clubs cannot be allowed to go unchallenged.
"The club can confirm that the necessary steps have been taken to begin this legal challenge."
SPFL chief executive Neil Doncaster had proposed the permanent alteration after three previous attempts at reconstruction failed to garner enough support.
He said: "Whilst a number of clubs were in favour of a new set-up, support was insufficient and we move forward with a fixture programme for 2020-21 on the current 12-10-10-10 structure."