Boris Johnson has long been a familiar face in British politics, so why does his ideology remain, in the words of his role-model Winston Churchill, “a riddle, wrapped in a mystery, inside an enigma”? It’s a puzzle to which there are two, and possibly three solutions, none of which are necessarily mutually exclusive.

The first possibility – and probably the one that holds most sway, even among many of his admirers – is that when it comes to Johnson and his principles, there is, to borrow from Gertrude Stein, simply no “there” there. According to this take, the prime minister is no more and no less than an amalgam of ambition and ego. Having conquered the dizzy (and for him, anyway, increasingly well-remunerated) heights of broadsheet column-writing, Johnson simply turned to politics as a glutton turns to dessert.

The second possibility – almost as widely canvassed as the first and clearly highly compatible with it – is that it suits Johnson’s essentially Machiavellian purposes to defy definition and to keep everyone guessing. What better way, after all, for the politician-as-prince to expand their circle of potential allies and preserve maximum room for manoeuvre so as to avoid being encumbered with positions and policy commitments that later on risk becoming unpopular or else just plain inconvenient?

The third possibility is somewhat more prosaic but may ultimately come closer to the truth – a truth obscured precisely because it is effectively hiding in plain sight. It is that, for all that he can be cast (with the presidential seal of approval, mind) as a Trumpian radical right-wing populist, Johnson is not so much “the special one” as a pretty bog-standard British rightwinger.

And as such, he is a politician who intuitively appreciates (with a little help from his friends, most obviously one Dominic Cummings and a variety of Fleet Street’s finest), how best to appeal to the millions of Brits (13,966,565 of them last Thursday anyway) for whom many of the Conservative party’s prejudices and presumptions are simply common sense.

Every one of Johnson’s predecessors, remember, made similarly heartwarming speeches on the steps of Number 10

Most fundamental of these is the idea that Britain is, can be, and should be, Great – the clue, as they say, is in the name. To call that belief a sense of manifest destiny would be an exaggeration. But it is a patriotic attachment to the idea (however illusory) of an island nation, albeit one with global interests and reach, that is fundamentally unique and, yes, better than many of its closest neighbours, especially those unfortunate enough not to speak English – or else to speak it with a Scottish or southern Irish accent.

But this is far from the only Tory truth to be held as self-evident by Johnson and those who voted for him. Just as important is the idea that the state, whose first duty is to uphold law and order, should neither grow too big nor try to do for people what they should do for themselves – with the number of people seen as deserving of help taken to be much smaller (since at root it includes only the very elderly, the visibly infirm and, where they’re not “feral”, children) than is probably the case.

This supposed common sense also applies to tax and spending. Both, like government regulation, should be kept as low as possible since the money is presumed to come ultimately from individuals and businesses who know better what to do with their hard-earned cash than a bunch of bureaucrats in Whitehall or in the town hall. Nationally, the sums, to coin yet another cliche, have to add up. Austerity is therefore a regrettable but wholly rational response when things are tight.

All this links Johnson firmly with his predecessors – Margaret Thatcher, John Major, David Cameron and Theresa May. So does (with Thatcher as the exception that proves the rule) his eagerness – on full display in his remarks in Downing Street on Friday – to employ that emptiest of empty signifiers, “one-nation Conservatism”.

Each and every one of the prime minister’s predecessors, remember, made similarly heartwarming speeches on the steps of No 10 about healing a divided country, only to walk through its shiny black door and proceed to do pretty much the opposite.

The real Boris Johnson? Meet the new boss, same as the old boss.

Tim Bale is professor of politics at Queen Mary University of London and author of The Conservative Party from Thatcher to Cameron