Captain Fiona Coghlan and her team-mates tore into the hosts at Esher RFC and were deservedly level at the break - 6-6.
Munster's Niamh Briggs and Katy Mclean scored a brace of penalties each, but converted tries from English skipper Mclean and Amy Turner put the game beyond Ireland's reach.
It was a flattering final scoreline for the champions, who needed an inspirational 57th minute try from their captain to swing this cracking contest in their favour.
The girls in green had been more than a match for them up to that point and only handling errors had prevented the visitors from completing some potent attacking moves.
Playing with huge skill and ambition, Philip Doyle's Irish side moved the ball wide at every opportunity and had the English defence stretched particularly in the first half.
Ireland, boosted by home wins over Italy, Wales and Scotland, established an early foothold in English territory. With Joy Neville and Claire Molloy rampaging forward from turnover ball, they soon had the first scoring chance.
Briggs punished England for not rolling away by slotting a sixth minute penalty, with some adventurous play then getting the pacy Ashleigh Baxter, Niamh Kavanagh and Alison Miller involved.
Ireland were showing great control of possession at this stage, rucking strongly where Neville, Laura Guest and Gillian Bourke all excelled.
A powerful run on the right from Katherine Merchant went unrewarded as the English infringed at the breakdown five metres out from the try-line.
Crucial tackles from Briggs and Baxter thwarted England as they got their attack going, and Merchant again punctured the Irish defence with a dazzling break.
Mclean brought the hosts level with a 21st minute penalty from straight in front of the posts, but Ireland were quickly back on the attack with incisive running from Kavanagh and Miller again.
Lynne Cantwell was unfortunate to give away a central penalty after doing well to mop up a bouncing ball, and Mclean landed the resulting kick into the wind.
England were whistled up for obstruction from the restart though, and Briggs' rapier right boot had Ireland back level at 6-6.
The Irish backs and forwards then combined down the right after a strong surge from centre Grace Davitt, with Bourke, Sophie Spence and Kavanagh bringing the visitors up towards the England 22.
Both Briggs and Mclean missed late penalties as a fiercely competitive first half came to a close with Ireland still in contention for their maiden victory over England in 17 Test meetings.
England got on the front foot when the game resumed, but a terrific break from impressive lock Spence got Ireland firing again.
They went for a lineout from a penalty yet England defended the maul and won the decision at the breakdown, with Mclean clearing to touch.
Gritty play at a subsequent ruck from Cantwell kept Ireland going forward and great hands sent Davitt on a diagonal run up towards the home 22.
Spence and her second row partner Marie Louise Reilly increased their influence in the loose, however full-back Scarratt swung over a 54th minute penalty to nudge England ahead at 9-6.
With the hour mark in sight, a clever move in midfield released Mclean for a devastating burst which saw Ireland caught flatfooted and the English skipper skated over to the right of the posts.
It was a momentum-swinging try and Mclean's conversion put 10 points between the sides as England's confidence grew.
The hosts could not turn their territorial dominance into further points though, with Scarratt and Mclean both missing kickable penalties.
But Ireland were now exerting less and less influence on proceedings as England's experienced bench became an influence. Replacement hooker Turner burrowed over from close range for a 71st minute try which effectively sealed the result.
Even still, Ireland emerged with immense credit from the game as they reached into their reserves of energy to produce a strong finish.
Full-back Baxter, one of the finds of the Championship, led a sparkling counter attack on the left as Doyle's charges pressed for a consolation try that their efforts deserved.
It looked like they might get it when they set up a close-in lineout and then won a turnover five metres out from the line.
The opportunity was lost though when Mclean ripped the ball away from Cantwell and England's defence, which had only conceded six points in their previous four games, held firm.
It was a record seventh successive Six Nations crown for the leading lights of European women's rugby.
Although on this evidence, the gap is definitely closing. Coghlan and her colleagues can hold their heads at the end of a truly inspirational campaign where this new-look team had knitted together in terrific fashion.
They look set to finish third in the final Six Nations table for a fourth year in-a-row. Second place will be theirs only if Wales win at home to France tomorrow.
Referee: Nicky Inwood (New Zealand)