In the past couple of days one of Sir Bradley Wiggins’s principal rivals in his teenage years, the Hemel Hempstead cyclist Sam Collins, has been posting photographs on social media of the pair in their junior and under-16 racing days. The images show two gangly lads against backgrounds as diverse as Walthamstow High Street and an eerily empty Manchester Velodrome, baggy jerseys, crew-cuts and awkward smiles. They mark a point in time, a generation ago, when amateurs in west London headed for their races in the Middlesex lanes or on the unopened Hayes bypass fearing the possible arrival of one of the country’s most talented youngsters, with the inevitable kicking that would entail.

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Wiggins’s retirement, announced through his Instagram page on 28 December, marks the end of a drawn-out departure – spanning the 20 months since his last race for Team Sky in April 2015 – but as those photographs emphasise, his exit also denotes the end of an era. The “Kid from Kilburn” was the last remaining member of the Great Britain able-bodied cycling squad who had begun competing in the mid-1990s, before the transformative era of lottery funding started under the direction of Peter Keen in 1998.

Wiggins has left his sport as Great Britain’s most decorated Olympian and boasting one of the finest all-round records cycling has ever seen: a Tour de France win, multiple stage race victories, the coveted one-hour record, world and Olympic titles on both track and road, and world titles in the Madison relay. His title in Manchester sticks in the mind, so too his and Rob Hayles’s last-gasp effort for a bronze medal in Athens. He can stake a reasonable claim to be the most versatile winner the sport of cycling has known since Eddy Merckx.

In the 20 or so years since those photographs were taken Wiggins has been at the heart of cycling’s metamorphosis from an arcane backwater to the British sporting mainstream, with a wealth of household names from Laura Kenny to Mark Cavendish, a host of high-profile events, a multiplicity of teams, huge participation figures and booming bike sales. It would be facile to pin all this on Wiggins’ shoulders alone but his string of successes played a persistent part in raising the sport’s profile, year after year since the Athens Olympics.

One key to Wiggins’s high profile is his chameleon personality. He has constantly reinvented himself via a wealth of contradiction – cycling historian riding the most modern kit with a period twist, Kid from Kilburn and rugby league aficionado, two-wheeled Modfather with the most famous sideburns in the country, man of the cycling grassroots once spotted at a polo club, clowning comedian and misanthrope, grumpy socialist knight of the realm, Team Sky leader who founded his eponymous squad to be the opposite of the Murdoch monolith. That in turn means that most fans can project something of themselves on to the “Wiggo” persona.

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And whereas fellow Olympians such as Sir Chris Hoy and Victoria Pendleton were seen only on television screens and in velodromes, Wiggins was the exception who successfully made the cross-over from the track to road racing, competing in his first Tour de France in 2006. When the Tour of Britain was relaunched in 2004, shortly after he took his first gold medal, at Athens, his was the name written on thousands of roadside posters.

From the moment he moved to the nascent Team Sky at the end of 2009, however, he has acutely divided public opinion, much as his team have done. He could win over a press conference – as he did at the end of the 2012 Tour and prior to the 2015 Paris-Roubaix – and make crowd-pleasing quips, such as his comment on receiving the yellow jersey in Paris that it was time to pull the raffle tickets, but that same year he produced probably the most expletive-laden rant to leave the lips of a Tour winner when asked about persistent online speculation that his and Sky’s performances were simply too good to be completely natural.

Those divisions have deepened since the Fancy Bears hackers leaked Wiggins’s therapeutic use exemption (TUE) certificates in mid-September, revealing that he had been administered the powerful corticosteroid triamcinolone before the 2011 and 2012 Tours de France and the 2013 Giro d’Italia. The TUEs were in order, backed up by explanatory doctors’ notes saying they were needed to treat Wiggins’s pollen allergies, so no rules had been broken.

Given that, how one reacts to it boils down to gut feeling: my personal sense remains that, even while keeping within the rules, this travels a step too far into the grey zone of the ethical spectrum, particularly given Wiggins’s consistently hard line on doping and proven dopers, and Sky’s clearly stated policies on moving the sport away from its troubled past.

From the only full-length interview he gave after the leaking of his TUE details, it was clear Wiggins felt bitter about the reaction to the story, which was underlined by his comments at what amounted to his farewell press conference after the Gent Six. It was also impossible to avoid the sense that he felt the process had taken on a life of its own, as indeed it has since the opening of a UK Anti-Doping inquiry into the contents of a jiffy bag delivered to Team Sky on the day he took his breakthrough stage race victory at the Critérium du Dauphiné in 2011.

Precisely how sporting posterity will view Britain’s greatest cyclist will be conditioned in part by the outcome of that Ukad inquiry, the precise scope of which remains unclear. That could be the final irony in a career packed with contradiction: a man who craved control wherever possible, who could put structure into pretty much any sporting challenge, may now be dependent on others to define his legacy.