The Guardian today lays out the case as well as anyone of any political persuasion can - https://www.theguardian.com/commentisfree/2016/sep/10/why-would-eu-appease-deluded-brexiters
The lie direct of the Brexit campaign was that the European Union cost us £350m a week. The bigger lie, which some Leave supporters may even have believed, was that there were no hard choices. We could have it all. Immigration controls, prosperity, access to EU markets, without compliance with EU laws… Whatever we wanted, at no cost at all.
The article states the case of the consequences of these lying politicians entirely and succinctly.
Which honourable politicians will now stand up with the courage to say that Brexit was a sham and invalid?