Gordon Brown calls David Cameron a shallow salesman as if it is a bad thing. I am not sure. Mr Cameron's press conference yesterday was a masterclass in shallow salesmanship. If the Cabinet was watching, they would have been jealous. Team Gordon is drowning in deep waters. Its new motto should be: “Head for the shallow end!”

First lesson of sales: get there first. Thus the snap press conference. It is an alpha male thing. A friend of mine who has a new puppy was told that she had to eat her dinner before the dog was given his to show who was “pack leader”. This may be crude but, as a rule, animal-training tips also work in politics.

Second, never say why you are there. “You will be relieved to know that I am not going to mention the local election again,” cried Dave, his tie as red as the Labour rose. “Except to say ...” Then he mentioned the local elections, again and again. (The official gauge used by sketchwriters for these events is the gloatometer and yesterday it was reading 11 out of 10.)

Third, talk loads of twaddle. “People are asking: what next from the Conservative Party? How are you going to build on your success?” twittered Dave, shamelessly. “Let me explain something quite fundamental about how I see the job of prime minister.”

Ah, so that's it. Dave is playing prime minister for the day. “You have got to have a plan and that plan must have a real sense of focus. You cannot do everything at once and you should not try. You have got be incredibly stubborn in going for it.” Dave beamed, his face shiny with sweat in the heat. It is a new look. I always thought he was a “no sweat” guy. Now all that has changed but, don't forget, he is being prime ministerial.

We called his bluff. OK, prime minister Dave, what would you do about the 10p tax cut? Dave said that he would reopen the Budget. That seemed rather general. Any other details? Dave said that he would reopen the Budget. We thought it was just an echo, so asked again. “The first thing the Prime Minister has got to do is to say I am reopening my Budget!” So much for having a plan.

Dave was asked about low-income families. Gordon said that he feels their pain, didn't he? “I have been talking about this longer than the PM,” he snapped. “He has been very slow to understand what has happened in the shopping basket and at the pumps.”

Most politicians would stop there, but not Dave. “Yes, I am wealthy,” he announced. “I have a very well-paid job and so does my wife. But I drive my own car, I fill it up at the pumps and when diesel hits 121.9p, which I paid outside Chipping Norton a couple of weeks ago, it really struck me that this whole tank is costing me £10 to £15 more than previously.”

Dave looked outraged at this. He really is brilliant at dropping in the slightly personal detail. The “I'm wealthy” line takes chutzpah. And the use of “Chipping Norton” was a stroke of genius. It made the entire story-ette (title: I May Be Rich but I'm on Your Side) seem utterly credible.

Finally Dave was asked if he still cycles. “I didn't cycle this morning. I will certainly cycle tomorrow morning. I always cycle before PMQs to try to get the blood coursing through the veins. I even do it with John Humphrys now, I find that helps too!”

Now that is not just shallow, that is deeply shallow. And, in politics at the moment, that is a compliment.

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