Donald Macintyre's Sketch: Battle of the market square - how David Cameron cakewalked Boris Johnson

Just once in Newark’s Market Square today a woman said to Boris Johnson: “Can I shake your hand? You’re the only one who’s got any sense.” Johnson’s reaction – understandably, given that the Prime Minister was only a few yards away – was to mumble affably, if unconvincingly, “No, no, no,” as she accomplished her mission.

But their banter was wonderfully open to deconstruction. Especially at the bakery stall, where Cameron actually – wait for it – ruffled Boris’s hair, adding: “He’s had a haircut; he is looking very good.” The second of these propositions was debatable, for having gamely bought a glutinous-looking £1 Rocky Road cake, Cameron was insisting on sharing it with a hesitant mayor. “Boris, that’s a gift. You know you want it.” (Presumably the cake, rather than “my job”, though the second meaning was much more bankable than the first.)

Boris countered by suggesting Cameron “share some of [his] baking tips?” and announcing that “the Prime Minister is a well-known baker”. It’s doubtless wholly unfair to think he was suggesting his fellow old Etonian should stick to bread-making rather than running the country. But by now he had lost the round. The PM repeatedly told voters: “I’ve brought the Mayor of London with me.” Which was possibly translatable as: “I’ve dragged him here kicking and screaming”, but with a clear subtext that he, Cameron, was well in charge.

Not everything went perfectly for the PM. These events bizarrely combine (very) small talk and actual politics. As in PM to first man: “You’re putting your tomatoes in? Outside or inside? We’ve had our last frost? We’re going to be all right? Anyway I hope you’ll be backing him [the Tory candidate, Robert Jenrick, who seemed tongue-tied by awe during the whole visit] next Thursday.” Second man: “Mr Cameron, when are you going to do something about the theft of Palestine?”

And replying to a challenge by a picture framer called Steve Buxton that he couldn’t promise to reduce VAT because of the “mess left by Labour” he was encumbered by still having his mouth stubbornly full of Rocky Road.

To an ex-miner named Brian Boby, who complained he had run down public services, Cameron said there were more doctors and nurses since 2010 but that “we want to do more on the ambulance service particularly”. Since George Osborne has already announced better rail links for Newark, improved ambulance provision may follow. The Tories do not want to lose here.

Boris, who mainly confined himself to handing out leaflets while telling voters “Let me give you some bumf”, played no part in these dissections of the Coalition’s record. Maybe Cameron could have done with more help on that front. But at least he had out-patronised the Mayor, which is no mean feat.