Hearts have been consigned to a shortened season in the Scottish Championship after the final attempt at league reconstruction failed.
Only 16 of the 42 clubs backed plans for a 14-10-10-10 set-up following an informal vote.
The Scottish Professional Football League board has now "agreed to draw a line under reconstruction talks".
It was also confirmed that Championship clubs had approved a reduced 27-game campaign, which is scheduled to kick off in October.
SPFL Confirms 12-10-10-10 League Structure For Next Season Full details: https://t.co/sP1LSEJkFR pic.twitter.com/eA7rbgjsJ1 — SPFL (@spfl) June 15, 2020
The vote means Hearts, Partick Thistle and Stranraer have all had their relegation ratified – unless the Edinburgh club follow up with their threat of legal action and manage to get their fate reversed.
SPFL chief executive Neil Doncaster said: "In recent weeks, we've been consulting closely with our clubs regarding possible reconstruction and, based on the feedback we received, the board decided to ask all 42 clubs to give their views so that we could have absolute clarity, which we've achieved today.
"Whilst a number of clubs were in favour of a new divisional set-up, the support for it was insufficient and we will now move forward with a fixture programme for season 2020-21 based on the current 12-10-10-10 structure.
"Due to the restrictions forced upon us by the coronavirus outbreak, the Championship clubs also voted overwhelmingly to play each other three times next season, rather than four, which enables a later start to the Championship league season.
"Now that we have a confirmed structure for next season, the SPFL's fixturing team will begin work on the Premiership fixture list, which will start on the weekend of 1 August, and the Championship fixture list, which will start on the weekend of 17 October."
Initial talks on reconstruction were shelved when a number of top-flight clubs baulked at plans for a temporary reconstruction, which would have led to mass relegation in two years' time.
Further attempts from Hearts and Rangers to introduce a three-division set-up both failed to garner enough support before the SPFL executive took the initiative and suggested a permanent change involving an expanded top flight and league itself.
The proposal would have resulted in no relegation and divisional runners-up Inverness, Falkirk and Edinburgh City being promoted, while Highland League champions Brora Rangers and Lowland League winners Kelty Hearts would have joined the league after the pyramid play-offs were abandoned.
The SPFL would have pushed for a general meeting in seven days' time if there had been enough support but the numbers fell well short with some clubs not willing to rush permanent change.
The change would have required 11 of the 12 Premiership clubs voting in favour along with at least six Championship clubs and 75 per cent of the league overall.
Partick Thistle are now facing an uncertain year given no decision has been made on the fate of the League One and League Two seasons.
Lower-league clubs, mostly part-time, face major financial challenges given social-distancing rules could affect gate receipts and hospitality income, while Covid-19 testing regimes could prove costly.
