London Irish bounced back from their Heineken Cup last four loss to Toulouse to run in seven tries against relegated Leeds in the Guinness Premiership.
The visitors took the lead through Tom Biggs but tries from Faan Rautenbach, Topsy Ojo and Declan Danaher gave the Exiles a 17-10 lead interval lead.
After Tomas de Vedia scored a fourth, Leeds hit back through Hendrie Fourie.
But Irish rounded things off through a Paul Hodgson try, a penalty try and a superb solo effort from Shane Geraghty.
London Irish boss Brian Smith pays tribute to Peter Richards:
"Our tactics are to get our best rugby players on the pitch, and Pete is one of our best 15 rugby players.
"Paul Hodgson did well in his absence, but our thoughts are that we need to threaten in every position in the backline and Pete is a threat there.
"The fact that he can just change positions and play that far wide from what he's used to is a testament to his skill.
"To Pete's credit, he understands that we are not doing him any favours as far as the England team going to New Zealand is concerned, but that doesn't bother him.
"He's put the team first, and we need a threat at 13 with Delon Armitage and a few other boys injured, and that's the way we've chosen to go."
Leeds rugby director Stuart Lancaster:
"Unfortunately, we couldn't maintain what we did in the opening hour.
"That's been the story of our season. We made some crucial errors and the game slipped away."
London Irish: Ojo; De Vedia, Richards, Mapusua, Tagicakibau; Hickey, Hodgson; Dermody, Paice, Rautenbach, Hudson, Casey (capt), Danaher, Armitage, Thorpe.
Replacements: Lea'aetoa, Mackie, Johnson, Murphy, Fisher, Hewat, Geraghty.
Leeds: Hinton; Holtby, Burrell, Tuilagi, Biggs; Brooks, Bedford; MacDonald, Ma'asi, McGee, Hooper (capt), Myall, Oakley, Fourie, Balding.
Replacements: Hopcroft, Parkes, Lund, Paul, Edwards, Greendale, Armstrong.
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