Alex Hales and Jos Buttler were the individual record-breakers, with the former making England’s highest individual score of 171 in this format before Buttler set a new quickest 50 - from 22 balls.
Buttler (90no) and Eoin Morgan (57no) took the innings sixes tally to 16, their century stand blitzed in only 43 balls, as England eclipsed Sri Lanka’s previous record high of 443 for nine, which came against Holland and had stood for 10 years.
Buttler sealed the deal by hitting the final ball of the innings over cover for four off Hasan Ali.
His stage was brilliantly set by Hales, on his home ground, as he broke Robin Smith’s 23-year-old mark of 167 not out - only to be lbw to the very next ball from Hasan.
Buttler took his cue, from the opener’s second-wicket stand of 248 with Joe Root (85), to blast that fastest half-century - with six sixes and three fours.
Hales had hit 22 fours and four sixes from 122 balls to help put England in an outstanding position to wrap up the Royal London Series.
Unbeaten in white-ball cricket this season, another victory here will put them 3-0 up with only two to play - and it soon became difficult to see how Pakistan might get competitive.
Hales’ fourth ODI hundred marked a return to form, after his poor end to the Test summer - while Root took his sequence of successive ODI half-centuries to five.
England blazed away from the outset, after Morgan won the toss on a glorious afternoon, Jason Roy’s departure to a gloved pull behind off Hasan barely checking momentum. The introduction of spin briefly did so. But when Wahab Riaz returned, Hales completed his fifty with a fine pull.
He sliced an edge high but just short of third-man off Wahab, and then in the same bowler’s next over pulled a no-ball into the hands of deep square-leg - therefore escaping twice, on 59 and 72.
Mohammad Nawaz’s first five overs remarkably yielded only 11 runs. But Hales clubbed 11 of the 13 off his next, and then 19 of the 20 when Azhar Ali chanced an over of his own leg-spin.
Hales was past his hundred by the time Azhar had a chance of revenge, but he put down a sharp chance at extra-cover - off Yasir Shah this time.
Hales’ only remaining moment of concern came a single short of history when he had to survive a review for lbw.
That delivery from Hasan pitched outside leg-stump.
But one more precious four later, Hales was pinned in the crease - sparking a second standing ovation in a matter of minutes, as he walked off.
Root fell in the next over, edging behind off Nawaz.
There was some cruel treatment to come for the slow left-armer, though, as the sixes began to rain - including three in his final over as England’s pedigree big-hitters gorged 135 in the last 10 overs.
There were 26 in one from Shoaib Malik, including four Buttler sixes to sprint past Paul Collingwood into the record books.
The ground was not big enough in an unbroken stand of 161.
Pakistan’s frazzled misery was summed up when Yasir dropped a simple catch at point to reprieve Morgan on 14 off Wahab, and even more so when the left-armer bowled Buttler with a no-ball.
It became a formality that England would pass their previous highest total of 408 for nine - against New Zealand at Edgbaston last year - and from the last ball, Buttler made them world-record breakers too.