Luton have become only the fourth team to suffer back-to-back relegations from the Premier League all the way to League One after a 5-3 defeat at West Brom.
A three-match winning streak had lifted the Hatters temporarily out of the Championship's bottom three heading into Saturday's trip to the Hawthorns, needing only to match or better Hull City's result at Portsmouth to remain in the second tier.
But a punishing first-half collapse against West Brom - conceding three times before shipping another two in the second period - made the task virtually impossible for Matt Bloomfield's side, despite scoring three themselves.
Hull stay up by the narrowest of margins having posted a superior goal difference to Luton after earning a 1-1 draw at Portsmouth to finish level on 49 points with a 14-goal advantage.
Luton join Plymouth Argyle and Cardiff City as those demoted to the third tier.
How Luton suffered double relegation
Despite going into the game on the back of three straight wins, Luton never looked like extending that run once managerless Albion clicked into gear.
The Hatters become the first club since Sunderland in 2018 to drop from the top flight to League One in consecutive seasons and only the fourth in the Premier League era after Swindon in 1994-95 and Wolves in 2012-13.
In a dramatic start, fans were rewarded with early goals from both sides, Tom Fellows putting the hosts ahead in the seventh minute following a mistake by goalkeeper Thomas Kaminski, before Millenic Alli cut inside smartly to sweep beyond Josh Griffiths.
Two goals in four minutes then hammered any of Luton's lingering survival hopes.
USA striker Daryl Dike climbed above Amari'i Bell to head Albion back in front from Callum Styles' deep cross and turned provider three minutes later, sending Fellows through the middle for a neat, chipped finish over Kaminski.
Styles tapped home Albion's fourth on 57 minutes and Albion didn't have long to wait for a fifth as Styles' drive deflected off Thelo Aasgaard to beat Kaminski.
Jordan Clarke and Alli reduced the deficit but Luton celebrations were understandably muted. Their fate was sealed as away fans chanted 'You're not fit to wear the shirt'.
Bloomfield agonises over coming close to safety
Luton manager Matt Bloomfield:
"Agonising for us to get to 49 points and it not be enough to stay up. We're disappointed with the performance today, obviously. It's a painful moment.
"We left ourselves exposed at times but we had to try to chase the game. It's disappointing, and agonising to come so close. Those goals were damaging for us.
"To work so hard to get ourselves so close and fall at the final hurdle is particularly painful."
