The Falcons, seeking to slowdown their downward spiral, couldn’t pull off a victory in a must-win situation.

In an NFL era where wild swings are the norm and there are no dominant teams — thanks to parity and free agency — the Falcons were hoping to stop their losing streak and limp into their bye week with some dignity and respect.

As much dignity and respect that a 3-5 team could garner.

But the Detroit Lions, led by quarterback Matthew Stafford, stormed back to defeat the Falcons 22-21 at Wembley Stadium to spoil the franchise’s first regular-season appearance outside of North America.

The Falcons went down despite holding a 21-0 halftime lead.

“We came out sluggish and thought it was over,” Falcons running back Devonta Freeman said. “They came and continued to fight.”

The meltdown in the second half was not complete until Detroit kicker Matt Prater, a former Atlanta castoff, missed a 43-yard field goal and then made a 48-yarder as time expired, touching off a raucous celebration on the Lions’ sidelines.

“This one hurts as bad as any as I’ve ever played in,” Falcons guard Jon Asamoah said.

The Falcons dropped to 2-6, while the Lions improved to 6-2. The Falcons have now dropped five in a row and appeared headed for another high pick in the NFL draft.

After a stellar play by cornerback Desmond Trufant to thwart Detroit’s a potentially game-tying two-point conversion, the Falcons’ offense, which appeared unstoppable in the first half, couldn’t close the final 3:56 of the game.

The offense went on the move, but an untimely holding penalty stopped the clock and cost the Falcons about 45 seconds. Then wide receiver Julio Jones dropped a screen pass on third down-and-10 from Detroit’s 40, which allowed the Lions to get the ball back.

“It just feels like we let the team down,” Asamoah said. “We let the defense down. We had to keep it going.”

After a Matt Bosher punt, the Lions had the ball on their 7-yard with one timeout and 1:38 left.

Detroit quarterback Matthew Stafford tossed a 32-yard pass to Golden Tate on first down. It took the Lions eight plays to move down to the Falcons’ 25 with 4 seconds left. Prater’s first kick was wide right, but the Lions were called for delay of game.

Since the clock was stopped because the Lions spiked the ball on the previous play, there was no 10-second run off.

Prater nailed the 48-yard field goal attempt.

With that kick the Falcons’ 2014 season may have imploded.

Since the NFL went to the 12-team playoff format in 1990, no team has started the season 2-6 and made the playoffs.

The Falcons opened the season looking like a team ready to rebound from last season’s 4-12 debacle with a vengeance.

They pulled out thrilling 37-34 overtime victory over the New Orleans Saints in the opener.

They had a tough time against the defending AFC North champion Cincinnati, before shellacking Tampa Bay 56-14.

The descent started in Minnesota.

The Falcons were in a tough battle and took a 28-27 lead into the fourth quarter. The defense couldn’t stand up to a rookie quarterback and were gashed for plays of 29, 22 and 15 yards on the game-winning touchdown drive.

With linemen Justin Blalock, Joe Hawley and Lamar Holmes out of the game with injuries, the Falcons offense couldn’t keep up in the shootout.

Then things started to unravel.

The Falcons blew a 10-point late third quarter lead against the New York Giants and loss 30-20.

The Falcons battled early and faded against Chicago in a 27-13 defeat and were manhandled by Baltimore, 29-7.

After getting mauled in Baltimore, the Falcons didn’t bother to return to Atlanta and headed straight for London. It was probably a good thing that they dodged their howling fans and the acerbic sports talk show radio hosts.

Even the normally tamed Brian Finneran, a former Falcons wide receiver, was speculating about widespread firings if things didn’t go well in London early in the week on 680TheFan.

The Falcons stayed at a posh resort, The Grove and practiced at the Arsenal Gunners Football Club’s fields.

Owner Arthur Blank noted that the team and coaches appeared refreshed, happy and determined to get a win against the Lions.

Wide receiver Roddy White thought the time away helped the team to bond.

The Falcons repeatedly referenced the weak NFC South as a reason for why they could get the season turned around.

But big blunders by the Falcons helped to fuel Detroit’s rally.

On a third down-and-25 from Detroit’s 41, Falcons safety Kemal Ishmael allowed Detroit receiver Golden Tate to get behind him for a 59-yard touchdown to make it 21-10.

On the Falcons next possession, quarterback Matt Ryan tried to throw across the field and was intercepted by Detroit cornerback Cassius Vaughn. The play led to a 20-yard field goal by Prater to make it 21-13.

The Falcons stalled again and punted.

Detroit answered with a 13-play, 69-yard touchdown drive to close within two points, 21-19.

The Falcons were a different team after halftime.

“The big thing he kept saying was keep your foot on their throat,” tackle Jake Matthews said of Falcons coach Mike Smith’s halftime speech. “Keep them down. You got them where you want them. Keep making plays. Obviously, we didn’t do that.”