In a shock announcement on Friday, the Mayor of London's transport authority banned Uber from operating in the city.

This capitulation to London's powerful taxi union will spark a major political reaction from Uber's 3.5 million London users and 40,000 drivers.

Recognizing as much, Mayor Sadiq Khan, who supports the ban, sought to reassure Londoners that he remains pro-business. "As we move through the next stage of 21st century innovation," Khan said, "I want London to continue to be at the forefront of these developments and to be a natural home for exciting new companies that help Londoners by providing a better and more affordable service."

But while Khan repeated this business theme throughout his article, mentioning "innovation" seven times and "innovative" three times, he won't win over his detractors.

After all, this decision is self-evidently allergic to the economic dynamism that is the lifeblood of major cities. As I've explained, before they move to a city, businesses need to know that their risktaking offers a good prospect of long-term rewards. But whether it's a small startup or an existing big business, Khan has just proved that he puts special interests before opportunity. For a mayor who has otherwise done a good job, it's a big mistake.

It's a big mistake, because while Uber will continue operating as it appeals, the ruling will hurt those who drive for their livelihoods. About 40,000 mostly lower-income people, many of whom have taken out loans to pay for their vehicles, must now find another job or join the welfare lines.

Still, Khan's real vulnerability is the roughly 3.5 million individuals who love Uber for its far-cheaper alternative to London's traditional "black cab" taxis. 3.5 million people is a lot of votes and a good foundation for a protest movement, and Uber knows it.

But that also makes this an opportunity for conservatives to defend the free market and attract otherwise politically-liberal or politically-apathetic users to their cause.

Many London Uber users are young and have been integral in strengthening the socialist Labour Party leader, Jeremy Corbyn. And for that reason, Corbyn has kept his head down today: He knows he is vulnerable. As I say, conservatives should seize the initiative here by contrasting Uber's capitalist innovation with Venezuela's socialist dystopia (incidentally, Corbyn's team are devoted followers of the Venezuelan asylum).

Regardless, Uber is far from finished. The company will now implement a crisis response plan and mobilize its supporters to protest the decision. Uber has had significant success with this strategy in the past: When New York City Mayor Bill de Blasio tried to destroy the service, Uber mobilized its users and forced the liberal overlord to back down. If nothing else, expect Uber to engage in aggressive litigation and to support drivers in their own lawsuits against the city.