Collingwood (90) and Andrew Flintoff (43) put on 81 for the fourth wicket to revive the innings after England, who chose to bat, lost opener Ed Joyce (one) and skipper Michael Vaughan (six) as early as the sixth over.
Kevin Pietersen, the new world number one batsman, chipped in with a 47-ball 48 which included five boundaries.
The 30-year-old Collingwood kept one end intact and hit eight boundaries and three sixes during his stubborn 82-ball knock before he was finally run out in the last over.
Collingwood's knock saved England's blushes as they ran into a spirited Irish bowling attack
Ireland were given a good start by their lanky paceman Boyd Rankin who surprised Joyce, a former Irish international, with a sharp incoming delivery which hit the off-stump in the second over before forcing an edge off Vaughan to wicket-keeper Niall O'Brien.
The 6ft 7in fast bowler finished with 2-28 off his seven overs.
Pietersen, who initiated the recovery, hit three boundaries off Irish skipper Trent Johnston's opening over as he and Ian Bell (31) steadied the innings during their 66-run stand for the third wicket.
When it seemed Pietersen would put together a big score, he was smartly snapped up at mid-wicket by William Porterfield off Kyle McCallan.
Flintoff, who failed to score in England's first round defeat against New Zealand and was dropped from the team over late night drinking for the Canada match, looked threatening as he hit a boundary off the first ball he faced.
But the Irish bowlers kept a tight line and length and never allowed Flintoff to hit out. Flintoff finally chopped Johnston onto his stumps after hitting four boundaries during his 62-ball knock.
Collingwood, who realised the importance of slog overs, reached his fifty off 65 deliveries and then cut loose, adding a quickfire 51 for the sixth wicket with Paul Nixon, who scored 19.
Ireland, who upset former champions Pakistan by three wickets in a first round match to qualify for the Super Eights, bowled well early on an easy-paced wicket but conceded 65 off the last five overs to hand the inititiave back to England.
England 266 for 7 in 50 overs (Collingwood 90, Pietersen 48, Flintoff 43, Bell 31; Rankin 2 for 28, McCallan 1 for 38, Kevin O'Brien 1 for 26) Vs Ireland (yet to bat)