AP Photo/Kirsty Wigglesworth
Vermont senator Sanders was seen as the insurgent, left-wing candidate pitted against the deeply divisive Clinton during the race for the Democratic nomination.
While Clinton eventually secured the ticket, some believed that Sanders would have been more popular in a head-to-head contest with Republican candidate Trump.
An NBC / Wall Street Journal poll published in May found that Clinton and Trump were locked in a "dead heat" with each other in terms of voting intention, but if Sanders were the Democratic nominee, 53% of voters said they would support him, against 39% for Trump.
Larry, a health spokesman for the Green party who lives in Oxford, told Business Insider over the phone that "I think Bernard would have beaten Trump."
He said: "He would have gotten pretty much all the traditional Democratic votes, he would have got more young and independent votes than Clinton - because he always did [during the Democratic nomination contest] - and he would have got more of the white working class votes too."
Sanders believes that both Bernie and Trump appealed to "large parts of the country that have been particularly hard-hit by a failed type of globalisation," and noted that "Bernard did particularly well in some of those so-called rust belt states [where Trump was also popular]."
He emphasised, however, that Trump's solutions differed radically to those of Bernie.
"Bernard has a clear and consistent policy over thirty or forty years of recognising growing inequality. And inequality, of course, is shifting resources from the bulk of the population to the very rich. The idea that Trump will do something about that is not plausible," he said.
"In addition to that, Bernard came up with quite reasonable ways of tackling it. Trump's main way of tackling it was to attack immigrants," he added.
Bernie himself suggested on Wednesday that Trump's victory reflected widespread disillusionment with "the establishment."
He said: "Donald Trump tapped into the anger of a declining middle class that is sick and tired of establishment economics, establishment
Larry echoed his brother's comments, and said that voters "identified Clinton as part of that ruling group that they didn't feel had done well by them."