England's Vunipola sees red as Ireland ease to World Cup warm-up win
As happened to Owen Farrell last weekend, Vunipola saw his initial yellow card upgraded to a red by the recently introduced bunker review system.
Vunipola was dismissed for a head-high challenge on Andrew Porter early in the second half.
That offence threatens Vunipola's involvement at a World Cup where he is the only specialist No. 8 in England's squad for a tournament they start against Argentina in Marseille on September 9.
By that stage, Ireland were well on their way to a 12th successive victory that kept them top the top of the world rankings.
They scored five tries, all through their backs, with Bundee Aki, Garry Ringrose, James Lowe, Mack Hansen and Keith Earls -- winning his 100th cap off the bench -- all crossing England's line.
England, suffering a fourth defeat in five matches, managed a late try through replacement prop Kyle Sinckler.
But a fourth successive Test without a try by one of their backs pointed to the lacklustre state of England's attacking game.
'Lack of progress'
"Right now, I feel the same as every English fan feels -- disappointed with the result and disappointed with the feeling of a lack of progress in the areas we want to, and obviously going to 14 men again," England coach Steve Borthwick told Amazon Prime.
The former England captain added: "There will be a lot of things to take way from this and clearly we need to go through the process with Billy Vunipola."
England kicked off without Farrell, the son of Ireland coach Andy Farrell, after Borthwick decided to leave the fly-half out of his matchday 23 amid an ongoing disciplinary saga.
Owen Farrell faces an independent disciplinary panel on Tuesday after World Rugby, the sport's global governing body, appealed against the decision to downgrade his red card for a high shoulder-led challenge on Taine Basham to yellow.
An original hearing's overturning of the in-game decision made during England's 19-17 win over Wales at Twickenham last weekend sparked uproar throughout the global game.
George Ford took over at fly-half against Ireland, with back-row Courtney Lawes leading England in Farrell's absence.
Ford's penalty gave England an early lead before Ireland -- who defeated England in Dublin in March to seal a Six Nations Grand Slam -- hit back through Aki's try, after a fine break by Peter O'Mahony, with Ross Byrne adding a simple conversion.
Ringrose extended Ireland's lead to 12-3 just before the end of the half when the centre capitalised on Hansen's crossfield kick to dive over wide on the right.
With England down to 14 men after Vunipola was initially off the field for a yellow card, Lowe went over for a third try before fellow wing Hansen crossed following a fine long pass by fly-half Byrne.
Sinckler scored from a pick and go before Earls celebrated his 100th cap with a spectacular diving effort in at the corner after being sent in by Aki.
"It was a tough week with all of the attention on my 100th cap," said Earls.
"To get it the way it worked out, with a try against England, there is no better way to do it."
The 35-year-old added: "My journey has had more downs than ups but I will enjoy tonight.
"It will be a tough job now (for Andy Farrell) to select the 33 for the World Cup but we will wait and see."
Ireland wrap up their warm-up campaign against Samoa in Bayonne next Saturday, when England face Fiji at Twickenham.