There can be no better illustration of the march of technology than the changing shape of mobile phones.
It would be fair to say however that, since today marks 40 years since the first mobile phone call, the first 20 years offered not an awful lot in the way of technological progress, or at least not a patch on the past 20.
During the era White City was set, in 1993, mobile phones were still a relative novelty to the majority of the general public. As Ryan's sister Emma quite accurately points out, "only drug dealers and yuppies have mobile phones," and she wasn't far wrong, although the term "yuppie" did serve to accommodate a whole raft of professions.
Mobile phones prior to the 1990s were, by today's standards, unreliable, clunky, and unwieldy with the early Nokias and Motorolas around the size of your average housebrick. They were also expensive and even on standby, the batteries wouldn't last more than a few hours.
But by 1993 things were beginning to change. Along with the MicroTac, top, which was continuing to drive Motorola's dominance in terms of sturdiness and reliability, new manufacturers were beginning to make their presence felt. Ericsson, in the present day an also-ran in the smartphone market (along with Motorola, incidentally), had produced something which actually wasn't a lot bigger than an iPhone. Texting was unheard of then but these things were still such a novelty that just making a call was a thing of wonder.
Then along came the Sony CM H333, or the Mars Bar, which was about the size of a giant Mars Bar, incredibly light and could store three telephone numbers in its memory.
Due to their pocketable size and the credibility associated with owning them, the smaller mobiles were an instant hit among those operating outside the letter of the law, and they were readily adopted.
For Ryan, Mark, and Jimmy, life wouldn't have been the same without them.
There is a great study of the history of mobile phones by the University of Salford here and here