Southend were relegated from the Coca-Cola Championship after goals from Calvin Andrew, Matthew Spring and Besian Idrizaj dragged Steve Tilson's side down with rock-bottom Luton.
The Shrimpers needed a win to maintain any realistic chance of avoiding the drop back to League One after just one season.
But Andrew's 20th-minute strike left them with a mountain to climb and Spring all-but consigned them to joining Luton through the trapdoor shortly before the break.
Lee Bradbury pulled one back in the second half, but Idrizaj crushed any hopes of a great escape when he broke clear late on to bring the curtain down on Southend's Championship stint.
Southend have been far from disgraced this term, and can proudly claim to be the only side to knock Manchester United out of any competition so far following their famous Carling Cup win.
But while their Essex neighbours Colchester - who were promoted with Southend last season - have excelled by making Layer Road a fortress, the equally dilapidated Roots Hall has hosted just two home wins since New Year's Day which has ultimately been their downfall.
Their already slim hopes were also dealt a blow when their top scorers, striker Freddy Eastwood and winger Mark Gower, were ruled out with back injuries.
Luton's only motivation appeared to be booking a trip to the Essex seaside again next season by bringing Southend down with them, but they earned their first win under Kevin Blackwell and could yet avoid the division's wooden spoon.
They were first on the attack when David Bell forced a smart low save from Darryl Flahavan.
Jamal Campbell-Ryce created Southend's first decent shooting opportunity, but his drive was deflected over by Leon Barnett and from the resulting corner the Hatters went ahead.
Bell brought the ball clear down the left, skipped past Kevin Maher and sent in a high, curling cross towards the far post which Andrew controlled in an instant before coolly beating Flahavan.
Richie Foran squandered two golden chances to level, heading over with the goal gaping and mis-hitting a close-range volley.
Southend's afternoon got worse when skipper and player of the year Maher limped off with an ankle injury, before Peter Clarke put a close-range shot over.
And the Hatters, without a win since February, doubled their lead six minutes before the break when Bell's cross was headed clear only as far as Spring, who rifled the ball past the helpless Flahavan.
Bell had Flahavan scrambling to save a low shot shortly after break, before the lively winger hit a free-kick straight at the home goalkeeper.
Southend, to their credit, never stopped attacking and Bradbury forced a save from Dean Brill before Alan McCormack and Clarke sent efforts over.
Bradbury finally pulled one back in the 65th minute, turning and firing past Brill from inside the six-yard box following a goalmouth scramble.
Luton captain Chris Coyne's match ended prematurely after he was carried off following a Bradbury tackle which earned the striker a booking.
Lewis Hunt headed wastefully wide and Campbell-Ryce shot straight at Brill as Southend poured forward, but they were hit with a sucker-punch when Idrizaj, on loan from Liverpool, raced on to Spring's long clearance and tucked the ball past Flahavan.
Tempers flared a minute from time with a shoving match on the touchline as Southend's hopes were finally extinguished.
Teams:
Southend Flahavan, Francis, Clarke (Prior 90), Barrett,Hammell, Moussa, Maher (Hunt 31), McCormack, Campbell-Ryce,Bradbury, Foran (Ademeno 81).
Subs Not Used: Collis, Sodje.
Booked: Barrett, McCormack, Bradbury, Clarke.
Goals: Bradbury 66.
Luton Brill, Foley, Coyne (Langley 82), Barnett,Emanuel (Davis 61), Spring, O'Leary, Bell, Heikkinen,Andrew (Talbot 78), Idrizaj.
Subs Not Used: Keane, Brkovic.
Booked: Andrew, Barnett, Heikkinen, O'Leary.
Goals: Andrew 20, Spring 39, Idrizaj 87.
Southend are relegated
Att: 10,276
Ref: S Tanner (Somerset).