Johnson, despite his pledge not to speak at “loads” of campaign rallies, may rival Salmond in terms of being stopped for selfies by voters between now and EU referendum day on 23 June.
The popularity of Johnson is a source of massive frustration to his Labour opponents, as well as to his detractors in the Tories, who now must surely include longstanding friend and ally David Cameron.
Despite his twice election as mayor of London, under Johnson’s stewardship of the UK capital there has been criticism that public transport has not been made cheaper and more accessible, quite an alleged failing given that some of the mayor’s main powers are over the London Underground and London buses.
However, Johnson’s predecessor as mayor Ken Livingstone is widely viewed to have had some success in championing reduced public transport costs, most notably as Greater London Council (GLC) leader in the 1980s with his Fares Fair policy - that saw London Underground and bus fares in the capital reduced before the policy was declared illegal by the courts.
Despite expensive public transport accounting for a large chunk of the income of many Londoners, Johnson’s detractors have suggested that the issue has never been a priority for the mayor.
But whether Labour or Tory figures like it or not Johnson is the man of the moment and love or loathe him, the mayor has styled himself as a flamboyant politician with a style that one observer once commented was “so colourful that it made Joseph’s Dreamcoat look like a dirty mac”.
Of course political history is littered with charismatic politicians who were tipped to be Prime Minister, including figures like Michael Heseltine and Kenneth Clarke, both of whose ambitions were dented partly due to their Euro-enuthusiasm.
There was also the late Denis Healey for Labour, who many viewed as “the best Prime Minister Britain never had”, with the former chancellor missing out on leading his party.
But in a Tory Party, many of whose members are so obsessed with Euroscepticism that all political sense goes from their heads at the mention of the word, Johnson is unlikely to fail for the same reason as Heseltine and Clarke.
Beneath the bumbling and eccentric style of Johnson, lies a hugely ambitious, calculating and ruthless politician with a burning desire to get to Number 10 Downing Street.
By placing himself on the opposite side of the EU divide to Cameron he has in affect launched a Eurosceptic bid to be the next Tory leader, whatever denials may be made by the mayor and however much he protests Cameron should stay on regardless of the result on 23 June.
There is also a less charming side to Johnson than the public persona he has so effectively promoted, of an “eccentric lovable buffoon” who can regularly be spotted cycling his way along the streets of London.
An article in 2004 that Johnson penned in The Spectator magazine that stated Liverpudlians “wallow” in their “victim status”, attracted criticism from those who viewed the remarks as a slight on the victims of the Hillsborough disaster, in which 96 people lost their lives.
Johnson who also stated that people in Liverpool “cannot accept that they might have made any contribution to their misfortunes”, was a copybook example of the sort of remark that earned the Tories the label of the “nasty party”.
Although Johnson, then a Tory shadow minister, was dispatched by then party leader Michael Howard to Liverpool to issue a somewhat begrudging apology, the remarks arguably betray a view the mayor has of sections of society, however hard he may try to disguise that now with a more cuddly image.
But whether or not Johnson makes it to the top job or is beaten by chancellor George Osborne, who is likely to be his chief rival, it’s perhaps worth imagining how a Tory Party led by Johnson might fare.
Johnson is in many ways the archetypical celebrity politician, almost in the American mould, something which has inevitably drawn comparison with the tycoon and would-be Republican US presidential candidate Donald Trump.
Although controversially calling for the chancellor to cut the tax rate for the country’s wealthiest to just 40p at a time of unprecedented austerity, Johnson in fairness could never be accused of taking the same hardline racist tone that Trump has adopted in his own bid for the presidency.
Probably a much more accurate comparison would be with that of Ronald Reagan, the Holywood actor who went into politics when he was elected as the Republican governor of California, before winning two terms as US president in the 1980s, when he displayed a hardline on welfare and trade unions.
Despite his portrayed by many as “a bit of a cowboy” there was a darker side to the original Cold Warrior Reagan, who secretly and illegally, transferred funds from the proceeds of clandestine sales of military equipment supplied to Iran to military rebels seeking to overthrow the democratically elected left wing Sandinista government in Nicaragua in the 1980s, in what was to become known as the Iran-Contra affair.
But Reagan was also notable for a highly effective folksy campaigning style, that saw him remaining in the White House for most of the 1980s, drawing much of his support from traditional Democrats, union members and working-class voters – or to use the US term blue collar workers.
While its a great unknown whether Johnson will go on to emulate one of the most electorally successful American conservatives ever, there is a similarity in style in terms of promoting a “bumbling” image that saw both men outfox their opponents, that Johnson’s Tory rivals as well as Labour politicians may do well to take note of.