What does a bad Tory leader reach for when in a fix? Immigration, of course. Theresa May is reported to be planning to announce “strict immigration controls” in her party conference speech, the last refuge of the disreputable politician. Her record on immigration is one of such spectacular failure from every point of view that she might be wiser to divert attention elsewhere. But no: the Times reports that she is summoning a special immigration cabinet meeting on the eve of conference designed to rally the rebels.

Diane Abbott to announce Labour plans to overhaul visa policy Read more

For a good contrast between the parties, Diane Abbott, the shadow home secretary, today spells out a pragmatic, practical and politically canny immigration policy for Labour. Here’s another symbolic moment of contrast between the erratic behaviour of the bedlam party in power and the gradual laying down of solid policies by Labour, even if no one is paying much attention.

Migration remains politically explosive: mishandled, it always has the potential to sink Labour. Look how wickedly – and successfully – the leavers stirred race-hate and panic in the referendum, with the likes of Michael Gove mendaciously suggesting 80 million Turks were heading to the UK, while the Daily Mail’s front page daily splashed with dark-skinned men climbing off lorries, or rows of migrant criminal mugshots, devoid of context or statistic.

No wonder that in his revealing new book, The Perils of Perception: Why We’re Wrong About Nearly Everything, Bobby Duffy, of Ipsos Mori’s Research Institute, finds voters wildly misjudge the number of migrants here: they guess three times more – 34% – were born outside the UK than the real figure: 11.8%.

Labour will abandon the net migration target of below 100,000 a year, always an absurdity David Cameron plucked from the air. No government could hit a target that relies on whims about how many people emigrate. No random limit makes sense, ignoring as it does the state of the economy and the fluctuating needs of industries and public services.

Labour will abolish rigid targets for the insanely complex 15 different levels, tiers and types of visa, but use a flexible responsiveness to the need for workers, combined with better training of our own workforce to fill vacancies. Abbott was backed up by the Home Office’s former permanent secretary, Sir David Normington, who told the Today programme on Thursday that a fixed number was always unachievable, warning that “targets get discredited if they are never met.”

It was easy for Abbott to make mincemeat of the shambolic state of every aspect of immigration policy and its dysfunctional administration, as well as its “hostile environment” cruelties exposed in the Windrush scandal. May’s hateful Go Home vans were a stain on the country. Labour will stop shocking “rip-off” fees for visas and citizenship registration, which earn the Home Office up to 800% profits.

None of May’s migration system works, not the overstretched Border Force, the removals, detention or endless backlog of cases. Theresa May’s long Home Office tenure was a period of serious maladministration that should have disqualified her from the top job. Instead, Amber Rudd, her hapless successor, took the drop.

May’s refusal to take temporary students out of overall numbers was a sign of mulish obduracy that characterises all her policy-making. Only after years of NHS shortages has she finally abandoned limits on desperately needed doctors and nurses – but still not on care workers. The migration advisory committee recommended many more seasonal farm worker visas: finally she has relented to offer just 2,500 when farmers says they need 75,000 to stop produce rotting in the fields. In comparison, Abbott’s work visas, issued according to national need, are plain common sense. She says nothing yet on the crucial question of whether EU citizens will get preferential treatment: Labour waits to see the deal first.

Voters largely agree that migrants needed in key occupations should be let in. Read Ipsos Mori’s detailed polling on shifting attitudes, and the strongest views are mostly common sense. People don’t want an open door; they want to know who’s arriving, and they want efficient and humane deportation of those who shouldn’t be here. But they welcome those who contribute to the economy. Asked to choose between priorities, most people (64%) want to ensure those who have the right to be here are not wrongly forced to leave, even if this means that some illegal immigrants are not deported.

Note, too, that two thirds would support ID cards, which both Normington and Rudd floated again this week. Given the way people now routinely give out vast information to all and sundry in almost every online transaction, the privacy case is almost nugatory. If it would reassure those who worry that health, benefits and other services are used by immigrants with no entitlement, then Labour might do well to return to this previous plan. Last time it was, disastrously, proposed to cost each citizen £75. This time, why not simply issue free passports to every citizen (now costing £75), and make an ID card the valuable asset every new arrival acquires with their visa?

• Polly Toynbee is a Guardian columnist