In an age when every conceivable piece of information is available at the click of a button, details of the pop group United Colours of Sound are impressively thin on the ground.

In one incredibly low-resolution image of the band that exists in the far reaches of the internet there appears to be 10 members; in grainy YouTube footage of them performing England’s official 2003 Rugby World Cup song at Twickenham alongside UB40 there seems to only be five. But none of that quintet is the radio presenter and TV talent show vocal coach Carrie Grant, who was definitely part of the group at some point. Or was she?

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The answers to such questions are secondary, really – at least for the purposes of The Spin this week – to the mystery of how, at a London rooftop bar, on 8 May 2003, two of United Colours of Sound’s innumerable members found their hands resting on the unlikely shoulders of John Crawley and Chris Adams, while another wielded a budget bat in front of county cricket royalty. Throw in the addition of laughably bad Elvis Presley and Austin Powers “lookalikes” – a misnomer of epic proportions – and it is an image that failed to stand the test of time five minutes after the photographer first hit the shutter release as much as it does now, 21 years after it was taken to promote the inaugural ECB Twenty20 Cup campaign.

“I remember cringing when it came out,” says Adams. “We were used to doing unusual photoshoots for sponsors, but this stood out as a strange one.”

It did not feel like it at the time, but amid such undistinguished musical company cricket was about to change for ever. Within the dusty boardrooms of the England and Wales Cricket Board there had been a desire to modernise its product for some time. The impending end of tobacco sponsorship in British sport offered an excuse to ditch the long-running Benson & Hedges Cup and replace it with something that held wider appeal for the masses.

Armed with a £250,000 research budget funded by Channel 4, the primary cricket broadcaster of the time, the governing body conducted more than 30 focus groups and canvassed 4,500 people of all ages, backgrounds and demographics to understand what they wanted from domestic cricket in England. The verdict was something more accessible, both through delivery and timeframe.

Borrowing from a format that club cricketers had played for generations on weekday evenings, the idea for a 20-over tournament developed and the wheels put in motion for a form of the game that would , within two decades, usurp the entire structure of the sport.

The new competition sneaked through a vote of the 18 first-class counties by 11 to seven (Glamorgan, Middlesex, Northamptonshire, Somerset, Sussex, Warwickshire and Yorkshire were not initially keen, if you were wondering) and the eminent cricket reporters of the day were flown out to the then ECB chairman Lord MacLaurin’s holiday home in Valderrama, Spain, to sell them on the idea. It was through a group discussion with the journalists that the name Twenty20 first emerged.

By May 2003, the first season of professional T20 action was imminent when Stuart Robertson, the ECB’s marketing manager, invited media to the plush Kensington Roof Gardens in central London for a launch photoshoot that might well be described as infamous had it not been so preposterously forgettable.

“My God, I don’t know why we ended up with those entertainers,” laughs Robertson. “We did the best we could on the budget we had. I remember going out shopping to buy a trophy for the Twenty20 Cup and had about £1,500 to spend or maybe not even that much. It was nothing. I went down to the local sports trophy shop and just asked them for the biggest trophy I could get for that amount.”

One quirk that did not go unnoticed by press attending the event was the ECB’s top brass ditching their ties for the presentation. A new era truly had arrived.

The Sussex captain, Adams, and his Hampshire counterpart, Crawley, were afforded prime position for the photographers because their upcoming game on 13 June would be the first professional fixture ever played in the format. Not that anyone involved had the slightest inkling of how far T20 would go.

“It was all a bit of fun,” says Adams. “Swing hard and if you win a couple of games then great. If not then don’t worry about it because it probably won’t be around in two or three years. I remember having to walk out for a hat-trick ball to Wasim [Akram], which is never something you really want to be doing. But the match was a lot of fun.” Adams survived that delivery but Sussex lost by five runs as the new tournament flourished.

Given free rein to promote their games as they wanted, counties used a variety of methods to attract new audiences, from bouncy castles and hot tubs pitchside, to strapping a rubber duck onboard a remote control car and driving it on to the outfield to accompany batters dismissed without scoring.

From there things evolved rapidly. The rest of the cricketing world soon launched domestic T20 tournaments of their own, with the Indian Premier League at the top of the global pyramid, and a biennial T20 World Cup followed, the latest edition beginning in the West Indies and United States on Sunday week. In four years’ time, T20 cricket will cap its extraordinary growth when it becomes an Olympic sport.

What odds on United Colours of Sound to play at the opening ceremony?

This is an extract from the Guardian’s weekly cricket email, The Spin. To subscribe, just visit this page and follow the instructions.