Labour are catching up with the Tories, and it's all because of Theresa May's self-inflicted wobble over social care

Welcome to the Wobble. This is a traditional feature of modern election campaigns. It happens when a Conservative government is miles ahead in the opinion polls and then Labour starts to catch up. By ancient convention, it is supposed to occur in the final week of the campaign, but this time it seems to have come early.

I doubt if anyone at Conservative HQ has grabbed anyone by the lapels and said, “We are about to lose this election,” as Lord Young is said to have done to Norman Tebbit in 1987. But Theresa May, who doesn’t usually do social media, has posted a warning that, if she loses six seats, Jeremy Corbyn would be prime minister. This is untrue – she would lose her absolute majority, but she would have to lose about 24 seats to give Corbyn a chance of forming his “coalition of chaos” – but it does sound a bit like a lapel-grabbing moment.

This is curious, because the main question of this election remains by how much she is likely to increase her majority. Yet the Prime Minister did her best to induce a wobble with the launch of her manifesto. Quite unnecessarily, she included a proposal that has alarmed a lot of pensioners and indeed people who are related to pensioners. Not the withdrawal of winter fuel payments from better-off pensioners – that is popular, especially with working-class Labour voters who are thinking of voting Conservative, as a recent focus group in Bury found.

No, the problem with the Tory manifesto is the plan to withdraw free care visits from pensioners who own their own home. At present, pensioners are entitled to care at home if they have less than £23,250, excluding the value of their house. The manifesto proposes to change this to £100,000, but including the value of the house. Given that most houses in Britain are worth at least twice as much as this, this means a lot of people could lose out.

This is one of those policies designed by wonks to remove an anomaly that no politician should touch with a barge pole. The anomaly is that the value of your house is taken into account if you go into a care home, but not if you have home visits. So the Tory manifesto proposes to make the system more generous for a few of those who go into a care home, but less generous for those who stay in their own home and have visits.

Neat, rational and electorally disastrous. You would have thought that May and Philip Hammond, the Chancellor, would have learned their lesson by now. Hammond tried to equalise National Insurance contributions for the self-employed in March. The wonkocracy agreed it was essential to correct an anomaly that could cost the Exchequer billions over the years, but Hammond was forced to abandon the change – the main revenue-raising measure in his Budget – within days. Not only would some people lose out but they were protected by a manifesto promise. Now there is an irony. May has got rid of one vote-losing manifesto promise only to replace it with another.

The Labour Party was quick to label the social care plan a dementia tax, even though its leader revealed that he didn’t understand it. I know it is complicated, but a whole day after the proposals were published Jeremy Corbyn condemned the Tory plan to “cap” the amount of their own money someone could spend on social care at £100,000. This “goes nowhere near meeting the needs of somebody with extreme conditions who can easily spend £50,000 a year on their care”, he said, as Labour advisers and John McDonnell presumably buried their heads in their hands.

If Corbyn didn’t understand it, many of the people who might be affected certainly did. Its electoral impact is quite different from means-testing the winter fuel payment – that is a small, certain loss that most people think is fair. (Although Ruth Davidson, the Scottish Conservative leader, takes a different view and says it won’t apply in Scotland, because it is colder there.) And it is quite different from ending the “triple lock” for uprating the state pension, which will probably have no effect over the next five years. The dementia tax, on the other hand, threatens to take much of their wealth from pensioners who would otherwise have received care at home paid for by the taxpayer.

It may be that only one in six pensioners will need social care, but six out of six fear that the one might be them. And none of them is reassured by the Tory offer to take a charge on the value of their house that would be repayable on death. (This “death tax” option is currently available if you have to go into a home; the manifesto proposes to extend it to paying for care in your own home.)

What is baffling is why this proposal was in the manifesto at all. The means-testing of winter fuel payments was eye-catching enough. It marked a break from a policy that David Cameron had been bounced into, and it allows £2bn a year to be freed to pay for better social care. There was no need for the manifesto to spell out detailed changes that would produce winners and losers. You do not need a degree in psychology to know the fury of potential losers easily outweighs the gratitude of potential winners.

Nor do you need to be a genius to see that the plan hits the middle group of pensioners – poor pensioners aren’t affected and nor are the rich, if they have more than £23,250 in savings.

It was an unforced error that will lose the Conservatives votes. The Labour manifesto is more generous and less specific on the subject of social care. It won’t mean that May is going to lose those six seats she is so worried about, but it may mean that her majority will increase by less than it otherwise would have done.

This was a quite unnecessary self-inflicted wobble.