At Edgbaston, Ben Stokes and Eoin Morgan are leading England's recovery. The crowd is increasingly boisterous, sensing how Australia face being bundled out of the Champions Trophy in the group stages.

Steven Smith, Australia's captain, throws the ball to Moises Henriques, hoping that his medium pace can wangle a wicket. Stokes promptly smites Henriques over mid-on with ferocious power. After a solitary over, Henriques is whisked off - never to return, even as England cruise to victory. Henriques' fate was a metaphor for the plight of slowish medium-pace bowlers in ODI cricket now.

When the World Cup last came to England, in 1999, it was a triumph for the dibbly-dobblers. This breed looked distinctly unthreatening, trundling in to deliver the ball at under 80mph, often much slower. But, bowling during the middle overs, moving the ball a little off a tight off-stump line, normally from just short of a length, their very lack of pace became an advantage, rendering it easier for a captain to place the five fielders allowed outside the 30-yard circle - typically at long-off, deep extra cover, point, square leg and long-on.

New Zealand's Gavin Larsen, a flag-bearer for this species, conceded just 3.46 an over throughout the tournament, including 0 for 26 off ten overs against Australia; his compatriots Chris Harris and Nathan Astle were almost as effective.

Virtually every country had a dibbly-dobbler of their own - sometimes several. Often their selection was made easier because they were normally reliable contributors of runs too.

Recalled to bring stability after Australia's tumultuous start to the tournament, Tom Moody went for 4.31 runs an over. For India, 35-year-old Robin Singh decimated Sri Lanka with 5 for 31. England's Mark Ealham was outstanding, taking two wickets in every game and bowling his full allocation of overs each time. Neil Johnson's 12 wickets, including 3 for 27 in the win against South Africa, underpinned Zimbabwe's run to the Super Six; Guy Whittall was also useful. Auxiliary medium-pacers, picked more for their batting than bowling, were handy too: Phil Simmons conceded under 3.5 an over for West Indies; Hansie Cronje's wicket-to-wicket bowling was South Africa's insurance policy; Sourav Ganguly helped eliminate England. Only Pakistan lacked a dibbly-dobbler.

Now, in a global ODI event in the same country at the same time of year, this type of bowler is virtually extinct.

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"Why don't we see many medium-pacers anymore? There's a very obvious answer to that: the fielding restrictions," believes Adam Hollioake, one of the four medium-pacers in England's 1999 World Cup squad.

Top dibbly-dobblers of the late-'90s Chris Harris 203 Hansie Cronje 114 Gavin Larsen 113 Sourav Ganguly 100 Nathan Astle 99 Guy Whittall 88 Phil Simmons 83 Robin Singh 69 Mark Ealham 67 Tom Moody 52 Neil Johnson 35 Adam Hollioake 32 Ian Austin 6

There is a real sense that the dibbly-dobbler has been legislated out of existence. The introduction of three Powerplays from 2005 (one of ten overs, and two of five overs apiece) increased the number of overs with fielding restrictions from 15 to 20, squeezing the time when medium-pacers could be used. This lasted until 2012, when one five-over Powerplay was removed. But at the same time, another change was brought in, even more deleterious for dibbly-dobblers: the number of fielders allowed outside the 30-yard circle was reduced from five to four during normal overs. Since 2015, this rule has been relaxed in the last ten overs, when five fielders are now allowed out, and the batting Powerplay has been scrapped, but the restriction to four fielders outside the circle otherwise remains. More than any other type of bowler, medium-pacers are the losers.

"When you were allowed five men outside the circle, you'd run up and try and bowl the ball into positions where they had to hit the ball to where you had the most men," reflects Hollioake. "Now, you don't get away with that because you've got to have another fielder up: that makes it tougher for the medium-pacers."

Other tweaks to the game have also conspired against medium-pacers. The introduction of two new balls, from 2012, prevents the ball from going soft, rendering trundlers easier to hit.

Pitches have changed radically. In recent years there has been a big emphasis on ODI wickets with more pace - simultaneously encouraging fast bowlers, and batsmen to hit the ball over the top. John Bracewell, New Zealand coach from 2003 to 2008, observed a deliberate shift away from slow and low pitches in both home internationals and domestic matches during his stint, marginalising dibbly-dobblers. "Batters dominated until bowlers started bowling faster and spinners started spinning the ball."

All these developments have been accelerated by improvements in modern batting - in physiology, psychology and preparation, with a little help from modern bat technology, and the fact that boundaries are often being brought in. Most fundamentally, levels of batting skill have been transformed; the ability to hit the ball 360 degrees is now routine. So where once medium-pacers could bowl on off stump, now batsmen shuffle across to hit the ball to the leg side. They are also far more adept at hitting such bowlers behind the wicket, through dabs, scoops, sweeps or reverse sweeps - thereby opening up the entire field.

Or batsmen can simple thump medium-pacers over the top. In 2006, a six was hit once every 112 balls in ODI cricket; last year, a six was hit once every 59 balls. As the limits of ODI batting are pushed ever further, so average scores are hurtling upwards. In this new age, allowing a bowler like Larsen to take 1 for 35 from ten overs (nearly exactly his average ODI return) is deemed reprehensible. In the middle overs, medium-pacers wobbling the ball to off stump are now greeted with disdain.

"Batsmen are setting themselves up to hit balls from the top of off stump, and what prevents this is either pace, change-ups, height or odd actions," explains Trent Woodhill, a leading batting coach. "So medium-pacers have become a natural target. Their margin for error is so small it causes them to over-rely on change-ups, which makes them easier to read."

Improvements among lower-order batsmen, accelerated by T20 cricket, have also emboldened teams to be more aggressive earlier. It means, too, that selectors have less reason to select medium-pacers on account of their useful batting.

The decline in modern wicketkeeping standards has also hindered the dibbly-dobbler. Adroit keepers aided medium-pacers by standing up to the stumps, enabling them to effect dismissals - eight of Harris' 203 ODI wickets were stumped - and, just as significantly, keep batsmen in the crease, so limiting their options.

Now, international keepers are less accomplished standing up to the stumps, and in a sense, keepers have also become less important to medium-pacers because of the change in batsmen's psychology. Chris Read observes that while at the start of his career standing up to the stumps would impact how batsmen played, now they will charge down the wicket regardless.

In response to a game being tilted ever more in favour of batsmen, containment can only be achieved through aggressive bowling that takes wickets. The modern ODI game "makes it very hard for the medium-pacer to survive," says Hollioake. "You need more specialist bowlers - guys who are going to bowl at 85mph-plus or spin the ball both ways - whereas back in those days you could run up with the men out, bowl stump to stump and wait for the batsmen to make a mistake."

So unless medium-pace bowlers can move the ball in exceptional ways, the sport has little use for them. Even in home ODIs early in the summer, England routinely use two spinners, one more than in their entire 1999 World Cup squad. Meanwhile, they have gone from four medium-pacers to none.

The evolution of cricket has been most noticeable in batting, but it has not completely passed bowlers by: never have so many bowlers been able to deliver the ball at 90mph. New Zealand, the archetypal land of the medium-pacer, now have at least six bowlers capable of clearing 90mph. Bracewell believes the shift in New Zealand began with the onset of full professionalism in domestic cricket, in 2002, and has been accelerated by the IPL and other lucrative T20 leagues: "more genuine athletes are choosing cricket over rugby".

In the first IPL, not a single New Zealand fast bowler was picked up; in 2017, six quicks played. Improvements in training techniques, and the extra money in the sport also make it possible for fast bowlers to manage their schedules better to elongate their careers.

The dearth of medium-pacers has taken something from the game. To see Harris ambling in awkwardly, resembling a clubbie more than an international cricketer, and still flummox batsmen was affirmation of how cricket was a game that took all sorts. And yet, in many ways the fate of dibbly-dobblers should be celebrated.

"It would have been harder for me to be successful," says Hollioake of modern ODI cricket. But he still believes that the developments - and the death of the widely loathed middle overs of meandering, risk-averse cricket from both sides - are good for the game.

Really, the demise of medium pace in ODI cricket is emblematic of something much deeper: the evolution of modern sport. Premier League footballers cover a quarter more distance over the same playing time than those 40 years ago.

Steve Kerr, the head coach of the Golden State Warriors, put it best when asked if his team would lose to great NBA teams of yore. "They would all kill us," he said sarcastically. "The game gets worse as time goes on. Players are less talented than they used to be. The guys in the '50s would've destroyed everybody. It's weird how human evolution goes in reverse in sports. Players get weaker, smaller, less skilled. I don't know. I can't explain it."

More batsmen can clear the boundaries; more bowlers, in turn, can bowl at express pace. What killed the dibbly-dobbler? Sporting evolution did.