Joe Schmidt's team scored first through an early Jordan Larmour try but their hopes of clinching the win that would lift them to the summit of the global rankings at the expense of Wales quickly disintegrated.
The greatest danger England faced was not from impotent Ireland but sunburn as Twickenham roasted in temperatures that peaked at 30 degrees, yet they were well equipped for broiling conditions having spent 10 days in a heat camp in Treviso.
Itoje and Billy Vunipola were magnificent up front, while George Ford is arguing a strong case to reclaim the first five-eighth duties for the World Cup, but players excelled across the whole starting XV.
While England fans will be daring to dream would could unfold in Japan, their Irish counterparts must be questioning whether a team that laboured to third place in the Six Nations are in full reverse.
To add misfortune to misery, they also came off worst on the injury count as Cian Healy suffered an ankle injury before Conor Murray was withdrawn at halftime having earlier passed a head injury assessment.
In a performance riddled with errors and poor judgement calls, Ireland limp into back-to-back games against the Welsh.
Will this Twickenham humbling spark a highly-charged World Cup campaign? Or sow a seed of doubt before the plane has left for Japan?
History indicates little should be read into results from the warm-up period. Ireland's hopes are far from dashed.
• Scotland revelled in their Murrayfield comfort zone to overcome France 17-14 yesterday and restore some pride after their humiliation in Nice a week earlier.
The Scots took the lead for the first time with a quarter to go when centre Chris Harris hit the line at speed and barged past a couple of defenders to score. Greig Laidlaw converted, and the home side was inspired from being in front and held on.
While their intensity and defence was much improved after losing to France 32-3 a week ago, Scotland's effort in the World Cup warm-up were disjointed and full of basic errors.
