Boris may be correct that a majority of leavers voted for a quick, clean cut with the EU but the then chancellor George Osborne pointed out that for this to happen there would have to be a large cut in spending to make the country ready for life under WTO rules... two years later the government has done nothing to balance the books, the BOE hasn't protected the currency by increasing interest rates to above inflation and the only achievement from Mrs May is that she has negotiated a deal that ends Freedom of Movement whilst forcing the UK to keep its laws in alignment with the EU. End result is the worst of all worlds if we leave with a deal or leave without one!
Apparently, Boris is already sanguine about a second vote, saying Leave would win it easily despite the polls suggesting that circa 60 percent of the populace actually want to stay in the EU. The only way that Boris will get on to the final leadership ballot will be by saying a second vote is going to happen, thus appealing to the majority of remain Conservative MPs whilst at the same time telling leavers they can win such a vote. Once in power, all bets will be off.