But after 359 League and play-off matches, 150 players, five managers and two new owners the club can finally look forward to Championship football again.
Before Darragh MacAnthony’s arrival as owner and chairman in October, 2006, Posh used to treat consecutive seasons in the third tier as success, but now they were seen as obstacles to progress.
Here are the ups and downs (mostly downs) from a frustrating period in Posh history...

. Peterborough United v Lincoln City - 01/05/2021
At last Posh players and staff can celebrate promotion! Darragh MacAnthony is back row on the left. Photo: Joe Dent/theposh.com.

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2012-13: After losing the first seven games of the Championship season, Posh rallied so well they reached the final day of the campaign with a great chance of staying up. Unfortunately this time they were on the wrong end of late drama after Crystal Palace scored twice in the final 10 minutes to inflict a 3-2 defeat and send Darren Ferguson's Posh down. Posh fans were understandably distraught. Final Championship position: 22nd. Highlights: Some great football and a fantastic run of results in the second-half of the season. Dwight Gayle's class. Lowlights: The first seven games, the last 10 minutes.

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2013-14: MacAnthony had to talk boss Darren Ferguson out of quitting following the horror of relegation the previous season. Star striker Dwight Gayle was inevitably sold, but replaced by a club record signing in Britt Assombalonga from Watford. Assombalonga (pictured) did his bit with 23 League One goals (33 in all competitions), but after a brilliant start (Posh won 11 of their first 13 games) the team’s form tailed off into a sixth-placed finish and a place in the play-offs. Posh promptly lost 3-2 in the semi-final on aggregate to Leyton Orient. It was sad, but who would have thought Posh would not reach the play-offs again? Winning the JPT FInal at Wembley was a decent consolation prize. League One finish: 6th. Highlight: Some great football during that rapid start. Lowlights: Lee Tomlin smashing up Fergie’s office after a transfer bid from Celtic was rejected. He also suffered three red cards before a departure to MIddlesbrough in January. Losing 5-4 at Oldham after leading 3-0 and 4-2.

1.
2012-13: After losing the first seven games of the Championship season, Posh rallied so well they reached the final day of the campaign with a great chance of staying up. Unfortunately this time they were on the wrong end of late drama after Crystal Palace scored twice in the final 10 minutes to inflict a 3-2 defeat and send Darren Ferguson's Posh down. Posh fans were understandably distraught. Final Championship position: 22nd. Highlights: Some great football and a fantastic run of results in the second-half of the season. Dwight Gayle's class. Lowlights: The first seven games, the last 10 minutes.

2.
2013-14: MacAnthony had to talk boss Darren Ferguson out of quitting following the horror of relegation the previous season. Star striker Dwight Gayle was inevitably sold, but replaced by a club record signing in Britt Assombalonga from Watford. Assombalonga (pictured) did his bit with 23 League One goals (33 in all competitions), but after a brilliant start (Posh won 11 of their first 13 games) the team’s form tailed off into a sixth-placed finish and a place in the play-offs. Posh promptly lost 3-2 in the semi-final on aggregate to Leyton Orient. It was sad, but who would have thought Posh would not reach the play-offs again? Winning the JPT FInal at Wembley was a decent consolation prize. League One finish: 6th. Highlight: Some great football during that rapid start. Lowlights: Lee Tomlin smashing up Fergie’s office after a transfer bid from Celtic was rejected. He also suffered three red cards before a departure to MIddlesbrough in January. Losing 5-4 at Oldham after leading 3-0 and 4-2.

3.
2014:15: Assombalonga departed for Nottingham Forest for a big profit and Posh essentially splashed £500k on Luke James from Hartlepool as his replacement. Again Posh started okay, but Fergie’s side lost nine games out of 12 either side of Christmas and a 3-0 defeat at MK Dons in February led to the manager’s sacking. Ferguson is pictured during that game. Posh were in the bottom half at the time and although caretaker-boss Dave Robertson won his first four games in charge, there was to be no play-off challenge. League One finish: 9th. Highlight: James’ joy after a rare goal at Doncaster. Lowlight: Fergie bowing out on such a bad note.

4.
2015-16: Over-promoted Academy coach Robertson was dismissed after six League One games (4 points, 4 defeats), but MacAnthony horrified many Posh fans by replacing him with Graham Westley (pictured). Westley’s side did deliver some outstanding football and they were soon in the top six, but the January sale of in-form top scorer Conor Washington and some bizarre signings and managerial tinkering prompted a disappointing second half of the season and a rare bottom half finish. Westley didn’t make the end though. He left with two games to go. League One finish: 13th. Highlights: 5-1 win at Crewe, 4-0 win at Scunthorpe. Lowlight: Westley’s plot loss