Boris Johnson’s conversion to the sugar tax – how much politics is personal?

British prime ministers tend not to allow their personal experience to influence their government’s policy, writes John Rentoul

The prime minister said ‘I’ve changed my mind’ on obesity (Reuters TV)

The prime minister’s brush with death has changed him after all. There was some speculation at the time that it might have made him more pro-NHS, but supporting the health service is an absolute requirement of modern politics in any case.

It turns out, however, that Boris Johnson has told ministers and advisers “I’ve changed my mind” on obesity. Having in the past opposed the sugar tax brought in by George Osborne, and mocked the nanny-state instincts of other politicians, he now says: “We need to be much more interventionist.”

He is reported by James Forsyth, the well-connected political editor of The Spectator, to be convinced that he ended up in intensive care because of his weight. As a result, he is “obsessed” with promoting cycling as a way of easing overcrowding on public transport.

In fact, he always cycled when he was mayor of London, and did a great deal to encourage cycling then, building segregated cycle lanes and bringing in the popular bike hire scheme. Now he has an added reason for trying to get the whole of Britain “on its bike”.

British prime ministers tend not to allow their personal experience to influence their government’s policy. Theresa May performed a valuable service for fellow diabetics by showing that it was possible for them to do a high-pressure job, but she didn’t interfere with the department of health’s policy on the condition.

Nor did Gordon Brown, who is blind in one eye and has a torn retina in the other, take much interest in ophthalmic services. Tony Blair, who had a heart flutter corrected under local anaesthetic while he was in office, didn’t make a policy out of that either.

Yet many prime ministers develop obsessions. May seemed unaccountably attached to the idea of setting up new grammar schools, despite having no children; perhaps that was only ever a gesture designed for the right wing of the Conservative Party, but she never let it go, even though there was never any prospect of getting it through parliament, either after she lost her small majority or before.

In that respect it was like Margaret Thatcher’s support for the death penalty: it was a badge worn to impress the party; she never tried to do anything about it in government.

In Thatcher’s case it was another personal obsession that was her undoing: her sympathy for the “hardship” of the ratepayer – the small householder oppressed by the property tax levied by local councils, often Labour-controlled. Her single-minded pursuit of relief for such people led her to impose the poll tax, which was so unpopular that Tory MPs got rid of her rather than risk losing the 1992 election.

So far, Johnson does not risk that kind of revolt from changing his mind about the sugar tax and trying to encourage cycling, but there are political risks – as he used to acknowledge – in bossy politicians telling people they ought to lose a bit of weight.