Pakistan's Shoaib Akhtar and Australia's Brett Lee have been clearly the two most devastatingly destructive bowlers in world cricket over the last few years.

In modern times nobody else has been closer to the elusive 100 miles per hour mark (160.9kph).

This may have been an ultimate goal of these two rare gems but over the past few years an intriguing battle has ensued as they jostle for the title as the world's fastest bowler.

So close has the margin been between Shoaib and Lee that they have almost gone ball for ball, speed for speed, since Lee's emergence in December 1999. Before this, Shoaib held the mantle as the world's fastest bowler.

Early in 1999, Shoaib was timed at 154.5kph (96mph) in Sharjah, the same mark that he reached against South Africa in Durban the previous year. In May 1999, at the World Cup, Shoaib proved himself the undisputed fastest bowler in the world, by bowling at 153kph (95mph) in his opening spell against South Africa. He then produced the fastest ball of the tournament in the final against Australia, once again reaching 154.5kph (96mph).

In October 1999, the great Dennis Lillee wrote an article for the West Australian, suggesting the imminent arrival of a sensational new speedster to the world stage, a 22-year-old Australian, who at 19 had been clocked at 148kph (92mph). Although no name was mentioned, by December 1999 the cricketing world knew the name Brett Lee.

In Lee's first Test match he ripped one down at 154.1kph (95.77mph), signaling himself as a genuine express bowler of rare ilk. The two speedsters went head to head, trading missiles throughout the Australian summer, constantly bowling in excess of the 150kph mark, up to and over 154kph. One wickedly brutal waist-high full toss from Shoaib to Justin Langer recorded a horizontal velocity of 154.2kph (95.83mph), Langer's hand bore the brunt of the red missile.

It was January 23, 2000 when Lee bowled what was considered the fastest recorded opening spell in history. Lee was consistently between 150-154kph, with a top speed of 154.8kph, which he bowled twice. His third and fastest over of that spell will go down as one of the fastest overs in history, recording speeds of 153.2kph, 152.7kph, 153.9kph, 154.1kph, 154.5kph and 154.8kph, with an average speed of 153.9kph. But Shoaib was to come back with some pure speed of his own.

In the second one-day final of the 1999-2000 season at the MCG, Shoaib bowled an over based on raw, untamed aggression. His fourth over recorded the following speeds: 151.7kph, 152.2kph, 152.9kph, 154.7kph, 153.5kph and 153.1kph, the average being 153.0kph. The two men were fast and getting faster.

On March 28, 2000 in Sharjah, against South Africa, Shoaib bowled a ball which registered a phenomenal 156kph (97.0mph).

In early April in South Africa, at the climax of a gruelling international schedule, Lee had his chance to go for the gun and eclipse Shoaib's mark, set two weeks earlier. Lee produced a seemingly effortless, rhythmical display, netting him the same personal-best mark of 156kph (97.0mph). Not only was this mark reached once but twice in the same match; however, it was not bettered.

Both players suffered stresses and strains associated with their speed of bowling. Lee had operations on both ankles, found he had the first signs of a stress fracture in his back and, when fielding, he blew out the elbow of his bowling arm in an injury akin to those suffered by baseball pitchers.

When repairing the damaged elbow, Lee's specialist also repaired long-standing bone damage.

Shoaib constantly seemed to be breaking down and had no doubt been through the most horrendous period of his life so far. Shoaib was passed fit and ready for action in December 2000 and it was revealed by Pakistani officials that he had bowled at a speed of 158.4kph (98.45mph), most likely in practice. The fast man reached incredible highs and lows in New Zealand, bowling one of his most devastating spells with a fastest ball of 151kph (93.85mph), before breaking down and ultimately being reported by the officials.

In the second match of the tri-nation one-day series in England, a rusty, under-prepared Lee was a surprise inclusion to an injury-ravaged Australian bowling line-up. Lee looked weak and nervous in his return bout and could bowl no faster than 140kph.

Meanwhile, the Rawalpindi Express steamed in and in his first over recorded the super fast time of 152.85kph (95mph). But in his second over, he was to hurl the red sphere faster than any bowler in modern times. With the eighth ball of his spell, Shoaib bowled a 157.2kph (97.7mph) bullet.

Akhtar now stood alone as the fastest bowler in the world. He had just bowled a full 1.2kph faster than Lee's best of 156kph (97.0mph).

Only 3.25kph (2.02mph) now separated the Pakistani paceman from the world record, standing at 160.45kph (99.72mph). A further 0.45kph (0.28mph) past this point and Shoaib would see a major ambition reach fruition. The cricket equivalent of the four-minute mile or the 10-second 100-metre dash.

Not since December 1975 was anybody recorded bowling that fast in match conditions.

On that one day in Perth, Jeff Thomson had recorded release speeds on 200/400 frames per second photosonic cameras of 159.49kph and 160.45kph (99.7mph), less than 0.3mph short of the magical 100mph mark. In fact, two men considered in the 'fastest ever' category, Michael Holding (148.54kph) and Andy Roberts (150.67kph) were both 10kph slower than Thomson on that day and an unwell Dennis Lillee (139.03kph) was 20kph slower. As an interesting side point, Jeff Thomson was also recorded by conventional radar the following year at 160.58kph to win a "fastest bowler" competition.

"This fastest ball of modern times was released at a speed of 157.4kph. It was a short-pitched ball, so a greater amount of kinetic energy is taken from the ball when it collides with the pitch"

Lee was below his best during the Ashes, although in the fourth Test he did bowl a spell close to his best, bowling both the fastest over and fastest ball of the five-Test series. Lee's hostile over recorded an average speed of 148.3kph and peaked at 152.4kph.

In the meantime, Shoaib was making another comeback to the international arena following his injuries in England. The wait was not long as the Rawalpindi Express exceeded the 150kph mark (150.7kph) in his very first over.

A mere four matches later and Shoaib was given another forced absence as suspicious officials reported him once more. Ironically, Shoaib would bide his time with Brett Lee's club side Mosman as he waited for the process to take due course.

While Lee and Shoaib were together on Australia's eastern seaboard, a third genuine "express" bowler was emerging and a legitimate threat to Shoaib's crown. The new threat had not come from the youngsters Mfuneko Ngam of South Africa or Mohammad Sami of Pakistan, as was expected, as both were on the long road back from injury. But another South African, a 24-year-old peroxide blond power-pack had materialised after spending two years in the fast-bowling wilderness.

Back on December 10 1999, the then fiery red-headed Mornantau Hayward had stopped the gun at 151kph. His speed reading against England had stamped the 22-year-old as a 'fast man' of the future. But over the next 22 months, Nantie battled with poor form and injury which kept his speeds down mostly to the 130s (kph) and low 140s (kph).

In 2001 against Kenya, Hayward bowled a shock 152kph to the hapless Kenyans in a one-day international in South Africa. A few days later Hayward bowled a spell to Sachin Tendulkar which had the Little Master in all sorts of trouble.

In the first Test against India, Hayward bowled the ball that would indelibly stamp him into express bowling's "big three".

He produced a 154.4kph blinder. His fastest delivery and faster than Lee had bowled in 18 months.

In the third Test against New Zealand Lee rejoined the pace race. He bowled three stand-out balls in the match, two of them measuring 153kph and one touching in at 154.5kph. That was faster than he had bowled in Australia since his debut season in 1999-2000, only 1.5kph from his fastest ball and more importantly 0.1kph faster than Hayward's personal best set the previous month.

In the first South African Test in Adelaide, Hayward shocked both commentators and fans alike with his new-found pace.

In the second Test, Lee was back in the express lane again, bowling in the high 140s on occasion and breaking the 150kph barrier.

When the South African captain finally let Hayward loose for a long spell he came out swinging. He notched up speeds of 150.2kph and 150.1kph twice in a torrid spell. He was in the 150kph zone for the first time on Australian soil, but one ball in the middle of the spell was of special significance.

Hayward bowled a ball to Steve Waugh which came in at 154.3kph, just 0.2kph under Lee's fastest ball and only 0.1kph below his own quickest. Of particular note was that the ball was bowled to Steve Waugh and that Waugh came within a whisker of playing on as did Sachin Tendulkar.

Lee stopped the gun at the 150.5kph mark in the second innings of the third Test. But a new challenger was yet to emerge.

During the one-day international tri-series to follow, Shane Bond of New Zealand emerged from the pack.

In Bond's first two Tests, he notched top speeds of 142.3kph and 146.2kph, and then headed home to terrorise the hapless Bangladeshis. He returned to Australia as a fully-fledged and confident speedster.

Bond not only proved to be the best bowler of the tri-series series to follow in Australia, he often pushed Lee for the title of the fastest.

Lee's fastest ball of the summer came on January 11, 2002 against New Zealand, the ball registering 154.6kph. Just 0.1kph faster than the ball in Perth and once again, his fastest since the 156kph balls in April 2000.

On January 26, Bond joined the "big three" in the 150kph club. During one of the most devastating spells you're likely to see in one-day cricket, Bond bowled over Adam Gilchrist with a 151.2kph rip-snorter of a yorker.

Hayward's ankle injury gave a boost to another young paceman as Makhaya Ntini took over the reins as the No. 1 South African fast man. Ntini aspired to join the express pacemen's club and was constantly up around the high 140s (kph).

Ntini reached a pace peak in Australia towards the end of his tour, clocking up 149.7kph and joined the likes of Bond, Shoaib, Lee and Hayward. Just a few weeks later back home in South Africa he released a 151.4kph projectile on February 22 2002.

In just a few short months, the exclusive club of two had grown to five and still there was another to come.

On the first day of the second Test in South Africa, Lee blew away these newcomers with a 157.4kph rocket. The ball in question was called a no-ball but this does not affect the speed of the ball's release and thus the speed was to stand as the new benchmark. Lee also bowled a legal ball recorded at 157.3kph by the EDH company's speed recording devices and one in the third Test came in at 156.2kph.

His two fastest balls had eclipsed Shoaib's 157.2kph, recorded the previous June against Australia and Lee was now No 1. But while Lee should have been basking in the glory of his fastest ball, the media as a whole chose to concentrate on some off-hand remark by wicketkeeper and Australian team-mate Adam Gilchrist.

Gilchrist had chosen to rain on Lee's parade when he called into question the accuracy of the EDH speed guns. What Gilchrist failed to acknowledge was that the EDH guns actually track the ball through the air, giving an actual ball velocity at the time of release by the bowler and not when the ball smacks into his gloves some 40 or more metres away.

This fastest ball of modern times was released at a speed of 157.4kph. It was a short-pitched ball so a greater amount of kinetic energy is taken from the ball when it collides with the pitch. Such things as friction with the pitch, the ball being compressed out of shape, the noise of the ball striking the pitch and the extra distance the ball has to travel through the air (which also reacts on the ball) to reach the keeper, rob the ball of velocity. Thus a short-pitched delivery on a slow pitch will take longer to reach the keeper and will reach him at a lower velocity than a yorker released at the same speed.

The one-day internationals saw perennial speedster Jason Gillespie belatedly enter the domain of the world's fastest. With his shorter run-up and more economical action Gillespie had recorded 149-plus kph in Australia (149.7kph), India (149.1kph), England (149.5kph) and in South Africa.

But now it was his turn to annihilate the 150kph mark once and for all. In the fifth and sixth one-dayers Gillespie returned speeds of 151kph and 153.9kph respectively. And then there were six.

Shoaib responded by bursting out of the blocks in Sharjah, answering the critics with super-fast balls. In his first two matches he was timed at speeds of 156.2kph and 154.9kph. Already he had blown away the newcomers and Lee was in his sights. The 156.2kph delivery was Shoaib's second fastest delivery in international cricket.

On April 12, Shoaib was to shock the world with his new found pace. Bowling with pace like fire, he clocked in at 159.5kph and with another ball of 157.4kph just for good measure. Shoaib had just blown Lee's 157.4kph out of the water in an inspired burst.

Brett Lee makes a strident appeal AFP

On April 17, Shoaib proved that his fast times were no fluke, recording speeds of 159kph and 158.4kph.

In the first of three one-day internationals against New Zealand, the show which Shoaib put on can only be described as phenomenal. Shoaib took six wickets for 16 runs, clean-bowling four New Zealand batsmen and breaking a stump when Andre Adams had trouble connecting with the ball.

Shoaib had done it again as he sent a missile down at 159.9kph.

He was a mere 1.1kph shy of bursting through the 100-miles-per-hour barrier (160.9344kph) and half a kph or so away from Jeff Thomson's world-record 160.45kph recorded during the 1975 Perth Test. During the third and final one-dayer, Shoaib was to finally go where no man had gone before.

On April 27, Shoaib burst through the 100 miles-per hour (160.9344kph) barrier with a ball registering 161kph on a speed gun operated in the ground by a sponsor. The US-made Stalker radar gun was run by the high-tech firm Cybernet. The EDH radar however was inoperative at the time and this caused much confusion as to whether the time would stand. Shoaib also clocked 160kph on the Stalker device and 159.8kph on the EDH device when it was operational. The 161kph ball was the sixth ball of Shoaib's second over whilst Craig McMillan was facing. Shoaib can now lay claim to being the "Hundred Miles Per Hour Man", but only unofficially. The ICC has declined to make Shoaib's 161kph officially recognised, but this is not surprising as there is no policy in place to recognise bowling speeds.

Shoaib has been recorded as bowling faster than 100mph, but some will doubt this reading because it was not registered by either IDS Sports or EDH, which between them cover the majority of international cricket matches. Both IDS and EDH have measures in place to dispel false readings and both companies take the matter of recording bowling speeds very seriously. Whatever else, Shoaib is now the undisputed world champion of speed.

Whether he is the fastest bowler in history is another matter entirely and that title would most likely fall to Jeff Thomson. Thommo's speed was measured on only one day of a single Test match in 1975, his fastest ball on that day was 160.45kph. Those high-speed cameras are still the most accurate way of measuring bowling speeds and would be in operation today if not for the delay in receiving the results.

What we do know is that these past few weeks we have been able to witness the most inspired exhibition of fast bowling that many of us have ever seen. The scene is now set for a showdown of epic proportions as the world's two fastest bowlers go head-to-head in just a few weeks time, early June 2002.