|London Irish (15) 25|
|Tries: Narraway, Tikoirotuma, Paice Cons: Brophy-Clews 2 Pens: Brophy-Clews 2|
|Harlequins (22) 32|
|Tries: Walker 2, Chisholm, Sinckler Cons: Botica 2, Evans Pens: Botica, Evans|
London Irish suffered relegation from the Premiership as Harlequins battled to victory at the Madejski Stadium.
Quins ran in three tries in the opening 22 minutes as Charlie Walker crossed twice and Ross Chisholm dotted down.
The Exiles rallied with tries from Luke Narraway and Aseli Tikoirotuma to only trail 22-15 at half-time.
David Paice's score then levelled matters for Irish before a late try from Quins prop Kyle Sinckler sent Irish down to the Championship.
|Sunday's other Premiership report|
|Saracens finish top of the Premiership|
|Exeter leapfrog Wasps with win|
It is the first time Irish have dropped out of England's top flight since 1994, having won just four of their 21 league games so far this season.
Head coach Tom Coventry took charge of Irish at the start of the season after they finished 10th last year, but it took until Boxing Day for them to win their first league game.
Harlequins, who are losing director of rugby Conor O'Shea this summer when he goes to Italy, secured a bonus point with Sinckler's fourth try which moves them up to sixth above Sale in the table.
They host second-placed Exeter on the final day of the campaign, while Irish are at third-placed Wasps.
London Irish head coach Tom Coventry told BBC Radio Berkshire:
"It's a hugely bad day for the club. We're all disappointed.
"The ambition is to move forward and we've wanted to do that from the start. Maybe ambition has got ahead of us, I'm not sure.
"We'll wash all that out over the next few weeks and look at where things have gone wrong and what we could've done better.
"We fell short again today. We showed some dominance in some parts of our game, but not in enough places across the field."
On his own future in the job: "I've been brought over here on a three-year contract.
"If I'm part of the future going forward, then we've got a big challenge ahead. If not, then we'll wait and see."
Harlequins director of rugby Conor O'Shea:
"We started brilliant and we played some really good rugby.
"We knew it was going to be tough today, emotionally, against a team who were going to fight tooth and nail and they did.
"We're in control of our own destiny again and we look forward to Exeter next week. Our goal today was to, putting personal things aside, put London Irish down."
On former club Irish's relegation: "It's terrible. I just hope they come back very quickly.
"I know that Quins did it and so did Northampton. Both have come back since and won the Premiership.
"Twenty-one years ago I came to London to join Irish. I know there's great plans for the club and I just want to see them come to fruition.
"I'm sure they'll stick together and come out of the other side."
London Irish: Maitland; Lewington, Mulchrone, Williams, Tikoirotuma; Brophy-Clews, McKibbin; Smallbone, Paice, Aulika, Stooke, Symons, Narraway (capt), Cowan, Guest.
Replacements: Cruse, Harris, Franks, Sinclair, Treviranus, Allinson, Noakes, Hearn.
Harlequins: Chisholm; Yarde, Lowe, Stanley, Walker; Botica, Care (capt); Lambert, Gray, Collier, Horwill, Twomey, Clifford, Wallace, Easter.
Replacements: Ward, O Evans, Sinckler, Matthews, Luamanu, Dickson, N Evans, Marchant.