John Rentoul: Boris is riding the wrong cycle

His record as the Mayor of London has hardly been sparkling, even if he is appealing to the Tory right

There is no need to ask what Boris Johnson is up to. The Mayor of London is as see-through as cling film. He gave an interview to The Daily Telegraph, the house newspaper of traditional Conservatives, on Friday about his desire to cut the 50p top rate of income tax because he wants to be prime minister.

Downing Street was said to be relaxed about his contribution to the Chancellor's consultations on the Budget to be delivered in eight weeks' time. Having just read the second volume of Alastair Campbell's unexpurgated diaries, I can offer a translation. David Cameron and George Osborne are furious about Boris's posturing, but agree that they must not respond in public for fear of further distracting from their message.

Before I allow myself to be distracted from their message, then, let me set out what it is. It is that the Government has a "growth strategy". What a relief. The nation was worried that they might follow the policy of previous governments and say that economic growth was bad for the environment and the less we had of it the better.

Sir Richard Lambert, the outgoing director-general of the CBI, last week had accused the coalition of not having a "growth agenda". Mind you, this is not necessarily a cutting criticism. You can imagine what a growth agenda would look like. 1. Apologies. 2. Minutes of the previous meeting. 3. PowerPoint presentation by the Facilitation Convenor of the Deregulation Task Force (Growth Working Party). 4. AOB.

When Cameron and Osborne came to deliver their speeches in the Swiss ski resort of Davos, however, their strategy consisted mainly of using the word "growth" in different sentences. Cameron said "we have made the decision to prioritise growth", and promised that the Chancellor would shortly be announcing "our Budget for growth". This would be in sharp contrast to all those that had gone before. Who can forget all those occasions when Gordon Brown declared, "this is a Budget for contraction and I commend it to the House"? In his speech, Osborne spoke of a "new model of economic growth".

On closer inspection, the new model turned out to be the old model, that of fiscal orthodoxy, balancing the books. It was neatly summarised by this exchange at Prime Minister's Questions last week. Cameron: "If you do not deal with your debts, you will never have growth." Edward Miliband (that is what Hansard calls him): "If you do not have growth, you will never cut the deficit."

Of course, the real choice is not so stark: it is a matter of where to strike the balance between Keynesian stimulus to maintain demand and the need for sound money to maintain confidence. Last week's economic figures moved the centre of gravity of that debate a notch in favour of Ed Balls and against Osborne. They are both in favour of "growth"; the question is what governments should do to maximise it.

The thing about this debate is that anyone can join in, from any part of the political spectrum. Hence Boris's deliberately timed intervention from the Tory right. The right finds itself lined up with the Labour leadership against the argument that balancing the budget is the most important thing. Only it wants to keep the deficit big by cutting taxes, not by public spending.

Boris knows that much of his party believes that Cameron failed to win a majority last year because he was not right-wing enough. Boris must know that this Tory Bennism is foolish. He was only 14 at the time, but, as a well-read student of politics, he must know that this is the mirror image of Tony Benn's argument after the 1979 election that Labour lost because it wasn't left-wing enough.

Still, Boris is also clever enough to see a chance for positioning. Or more positioning, I should say, as he has been doing it for some time. And not all of it designed to appeal to the traditionalist right. He dismissed Cameron's broken society theme as "piffle", preferring a more optimistic take on modern Britain. He opposes Cameron's policy of capping immigration, arguing that open markets benefit a great trading city such as London (and by extension a great trading nation such as Britain).

To be blunt, Boris's record as Mayor has been disappointing. He was elected partly as someone who would get tough with the Tube unions and sort out public transport. All he has done is cry to Cameron to change the law on strike ballots while the Tube keeps grinding to a halt.

Overall, though, he has carved out a national image for himself as a pro-business, low-tax but broad-based politician. "Labour have created a climate that is miserable and anti-wealth creation and was resentful," he said last week. "It takes a real effort of political will to dispel that." That could be a popular growth agenda after the deficit has been tamed and if Cameron stumbles.

The mechanics of getting Boris back into Parliament are not difficult. Anyone with star quality, such as Benn himself in 1984 or Michael Portillo in 1999, can find a seat. But the timing is always going to be awkward. Boris will presumably be re-elected as Mayor of London next year and so won't be on hand if there is a sudden leadership crisis. His second term would run to 2016, a year after the 2015 general election. The London and national cycles are not scheduled to coincide until 2020.

By then, who knows who will have come to the fore? George Osborne may have acquired the gravitas due to a chancellor who happened to be there when growth resumed, and people have forgotten his misjudgements in opposition – not just in the bank crisis but in his earlier flirtation with a flat tax. Philip Hammond may have emerged as a personable and decent fellow in no way responsible for the failure of the high-speed rail project.

And though it was Ken Livingstone's idea, Boris may end up remembered as the chap who introduced a bike hire service in London.

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