Some sports stars dazzle on the pitch or earn headlines for their after-hours antics. Others lend their names to good causes. But it's unusual for a player in his early prime to take on a government as Manchester United striker Marcus Rashford has done.

In early summer, Rashford's campaign to extend Britain's free school-meal vouchers over the summer break got the cold shoulder from Boris Johnson's government. But such was the underlying logic of his demand, and the public support for the footballer's plea, that Johnson made a swift about-turn, allocating £120 million (about $156 million) for that period.

When the 22-year-old star argued that a further extension was needed to cover the autumn and winter school breaks, it should have been a simple matter of hitting the repeat button. The Government, however, refused. The backlash has shown the fragility of Johnson's new coalition of Conservative voters. It also suggests the public may be moving even farther to the Left of a government that has promised large amounts of spending.

Rashford is no ordinary sportsman. A hugely talented footballer with one of Europe's top clubs, he's a goalscoring super-celebrity and a regular for the England team.

But his personal narrative adds to his influencer status: raised by a single mother along with five other children, Rashford knew food poverty first-hand. Well before the pandemic, in October 2019, he set up a campaign with British department store Selfridges to provide essential items to the homeless over Christmas.

After Tory members of Parliament voted last week to defeat a motion from the opposition Labour Party to extend the voucher programme over the holidays, Rashford took to social media to express his despair. Then something remarkable happened.

Restaurants, pubs and cafés around the country stepped in to offer free meals to needy children over this week's autumn school break. Local authorities pledged help at Christmas, too. Nearly 900,000 people signed a petition calling for the Government to extend the meals programme, and Labour is threatening a new vote on the matter.

Even the players of Leeds United, a bitter rival of Rashford's team, donated to his campaign. It was as if David Cameron's moribund 2010 idea of the Big Society — the notion that charities and civic groups could replace parts of state provision — had come to life. Only this time it was a rebuke to a Tory prime minister rather than a validation of a Conservative ideal.

That's quite a blow to Johnson, whose biggest asset when he was elected last December was an uncanny ability to take the public's pulse, read a room and reach out across boundaries of age, income and education.

With one simple "no", Johnson has managed to set himself against a popular, black sports star, against the working-class northern English constituencies whose votes delivered his parliamentary majority — and seemingly against feeding hungry children at Christmas. It has been a communications disaster.

Of course, it stretches cynicism beyond credulity to think that Johnson or his ministers really don't care about children having enough to eat. They're just conflicted about the right approach and seemingly loath to accept ideas they haven't invented.

But why not engage with Rashford and the issues earlier? If there was justification for meal vouchers for deprived children over the summer lockdown, it looks like hair-splitting in the extreme to say it wouldn't be needed over Christmas when some state support has been cut back and unemployment is ticking upward.

Largely this is a disagreement over how to manage this problem, not one about fundamental principle, as Johnson concedes. And yet, the Government's alternatives to the Rashford plan of just extending the meal vouchers are inferior. That just fuels the impression that the Government hasn't thought carefully about an issue that ought to be paramount.

Ministers' claims that extra cash given to the councils this summer (£63 million ) will cover the cost merely strengthen Rashford's case. That money was expected to last only 12 weeks and wasn't specifically earmarked for school dinners.

The Government has increased the general British welfare payment, known as Universal Credit, which will help. That is also useful for getting money to families too proud to apply for free school meals. But the increased benefit is unlikely to be enough and isn't targeted at children themselves. If the Government is adamant it doesn't want to extend the voucher programme, it will have to find another way to do effectively the same thing.

The public response to Rashford's campaign is, ironically, a confirmation that Johnson's instincts for his party were correct. People are looking to government to level the playing field and provide some baseline protection right now. The open question, increasingly within his own party, too, is whether he's the leader to do it.

• Therese Raphael is a columnist for Bloomberg Opinion. She was editorial page editor of the Wall Street Journal Europe