The song uses fairly stripped back production, utilising a 2-step rhythm which was common in UK garage at the time.

It features members from So Solid Crew performing during the storm in front of fences full of people dancing.

[5] In a 2002 review, Pete Paphides in The Guardian said the track was "a brilliant idea" but that "not a single member of the collective uses their time to say anything remotely insightful.

[7] In a 2020 retrospective review of the single, The Quietus said the track "managed to capture the excitement of clubs and pirate radio, with MCs frantically passing the mic as they try to outdo each other in lyrical prowess, creative aggression bubbling beneath the surface.

[29] On 6 September 2019, So Solid Crew went to the Red Bull Music Studios, London, and remixed "21 Seconds" with Toddla T.[30] They were joined by D Double E, Ms Banks and DJ Q as they added new verses.