Won't it just go away. That's the view on much of the left when it comes to immigration: not the process itself, but the issue. The average British voter wants to renationalise the railways, increase taxes on the rich and radically reduce immigration. The first two issues are invariably conjured up as examples of an appetite for a left-wing populism, and with some justification. The problem for the left is that while, say, publicly owned rail will win a murmur of agreement from most if they are prompted, clamping down on immigration is a burning priority for millions. Over the summer – as Labour's ranks were swelled with Corbynistas – immigration became the number one concern of most voters. Half opted for immigration as their key priority: the pollsters Ipsos Mori have never recorded a higher level.

If a generally positive approach to immigration is your thing, the polling evidence is rather sobering. In the last few years has dropped out of the voters' top 5 concerns once. The British Social Attitudes Survey in 2013 found that 77% of people wanted immigration “reduced a lot” or “reduced a little”: “reducing it a lot” was chosen by over half of those polled. Among those pollsters regard as working-class – the left's key base – the level of hostility to current levels of immigration is even higher. Yes, younger voters are less hostile than Britons overall, three-quarters of whom believe immigration has been too high over the last decade, and nearly half think “much too high”, but don't get too excited. Well over half of 18 to 24 year olds think immigration has been too high over the last ten years, with just 29% who think it's about right. And then it gets even more complicated. For those with migrant heritage whose parents were born in Britain, according to the 2013 British Social Attitudes Survey, 82% want immigration reduced; among first and second generation migrants, the figure is significantly less, but still a very decisive 60%.

The polling is pretty conclusive: on economic issues, UKIP voters are frequently to the left of the British public as a whole, but their policy grievances above all else focuses on immigration. In the impending Oldham and Royton byelection, expect to see UKIP mercilessly zero in on immigration.

The left has failed comprehensively to offer a convincing story on immigration. It is little noted, but it is one of the few issues that the Blairite right and Corbynite left largely agree on. Both emphasise the economic benefits of immigration, not least given EU migrants tend to be younger tax-paying workers who claim fewer benefits and depend less on public services. Both extol the cultural benefits, too, particularly the community enrichment of metropolitan urban centres. Both highlight the two-way nature of migration: that millions of Britons exercise their rights to freely travel and work abroad. Immigrants are being used as scapegoats, add the left, for problems caused by our unjust economic system, not foreigners, like the failure to build affordable housing, protect skilled jobs, defend decent wages and fairly regulate the labour market. Anger should be directed at powerful interests, like poverty-paying employers, tax dodgers and financiers, instead.

Some regard anti-immigration sentiments as evidence of straightforward prejudice, to be tackled under the general umbrella of anti-racism campaigning. Another explanation is the pernicious role of the media. Now, I'm the first to critique the British press, largely run as it is by a tiny group of extremely rich media moguls; or indeed to point out that aspiring journalists are discriminated against on the basis of parental wealth rather than talent, through unpaid internships and expensive postgraduate qualifications. The evidence shows that people drastically overestimate the number of immigrants in Britain, the number of teenage pregnancies, the level of benefit fraud, the amount people receive in benefits, and so on. This is compelling evidence of a media that fails to educate and inform.

But my view is that the role of the media has become a crutch for the left, a convenient deflection from our own failure to convince and persuade. We fail to get traction, not because we have failed to communicate an inspiring alternative, but because the evil old media has brainwashed the public. This is clearly patronising, reducing sentient human beings to sheep or robots, lacking agency and programmed by media oligarchs. It is a defeatist attitude, too, because if millions of people can simply be instructed what to think by powerful forces in society, then we will never win any battle. It stops us from being critical of our own failures and seeking to address them.

Whatever the arguments, the evidence is overwhelming and compelling: the left have disastrously failed to persuade the large majority of the British public on immigration. As a consequence, the left fails to get a hearing on a whole range of other issues, too.

Privately, there are some left MPs and trade union leaders who want a debate over freedom of movement. But Labour's electoral coalition over immigration is, to say the least, unwieldy. The pollster Ian Warren identifies two groupings: “younger, liberal well-educated cosmopolitan voters living in diverse towns and cities” who live “in close proximity to recent migrants”, and believe that immigration is beneficial from both a cultural and economic perspective. Any shift to an anti-immigration posture would “send social media into meltdown”, but more crucially prompt significant defections to both the Greens and Lib Dems.

On the other hand, Warren identifies “the older blue-collar workers in ex-industrial areas and struggling households reliant on state benefits living in neighbourhoods which have seen relatively recent large influxes of migrants.” A sense of identity has been undermined by the rapid loss of traditional industry; and they feel as though they are competing “with recent migrants for the low-paid secondary jobs which remain”, as well as jobs and schools. An unapologetic pro-immigration position would provoke backlash from this wing of Labour's coalition, Warren believes, fuelling support for UKIP. Could it be, he suggests, that the “inconvenient truth” is Labour's electoral coalition represents “voters with divergent and perhaps irreconcilable opinions on the impact of immigration.” This goes some way to explain Labour's tortured recent positioning on immigration, as the party is buffeted between the pro-immigration and anti-immigration wings of its coalition.

In Scotland, once apparently impregnable Labour strongholds were swept away by the SNP. The danger many observers have identified is that a similar process could happen in northern working-class seats, not at the hands of a progressive civic nationalist party, but a hard right xenophobic party. The Oldham and Royton byelection will provide further evidence about the current extent of the rot.

The left is long overdue a debate on its strategy to immigration, starting with an acknowledgement that its current approach has self-evidently failed. Yes, we can rightly argue that social and economic insecurities are fuelling the intensity of anti-immigration backlash, even though the phenomenon cannot be reduced to that alone. Council houses need to be built; a state-led industrial strategy is needed to create skilled, well-paid, secure jobs; a genuine living wage needs to be fought for; workers' rights need instating, and so on. But while we can and should make the case for such an approach, these policies can only be implemented – and anti-immigration sentiments softened – if the left are in power in the first place. If we have nothing compelling to say on immigration now, that is an unlikely prospect.

A stance on the undercutting of wages, terms and conditions is clearly important. Employers use cheap and insecure labour, including agency and zero-hour contract workers, partly as a means of weakening the bargaining position of other workers. Some of this labour is foreign in origin, some is native British. Wherever they hail from, it is the employer, not them, at fault. Challenging this undercutting stands in very long-standing left traditions indeed: it is worth noting that the First International – or the International Workingmen's Association – of Karl Marx and Friedrich Engels was originally set up in the 1860s to challenge the use of foreign labour as strikebreakers. Yes, we need to focus on policies that are far more to blame for reducing the income of working people: the impending cuts to tax credits, for a start, as well as making the case for trade unions being empowered to improve the conditions of working people. But that doesn't mean ignoring undercutting. Indeed, the evidence suggests that former immigrants are hardest hit, because they are often competing for jobs that do not need a high level of written or spoken English.

Nonetheless, undercutting is an issue that affects the lower end of the labour market, and anti-immigrant sentiment is prevalent among both low-income and middle-income workers. Much has been made about the fact immigrants are a boon to the Treasury. But such economic benefits are completely abstract to most. That's why the left surely has to make the case for an 'immigration dividend': that communities with a higher level of immigration should receive extra funding, calculated on the basis of how many immigrants they have. This would make a real connection between the economic benefits of immigration uncovered by academic studies and the reality of people's lives.

Story-telling is important. Falling back on statistics to make a case demonstrably fails to persuade public opinion. When that little Syrian boy was found washed up on a Turkish beach, it had an impact on public opinion, because humans are naturally empathetic creatures, but that empathy is undermined when the humanity of a group of people are stripped away. Suddenly refugees became human beings again: story-telling humanises. Focusing on, say, personal experiences of being treated by foreign-born nurses and doctors in the NHS can be effective, too, because a large chunk of the population has experience of being treated by, say, Nigerian, Lithuanian or Bangladeshi careworkers. Making arguments that connect with people emotionally, rather than treating them as statistic-computing machines, is more effective.

At the same time, though, is it really healthy that we are recruiting one in four nurses abroad because of cuts to nurse training places? Is stealing nurses from poorer countries who need them far more desperately than we do a good thing? I don't think so. Here is an argument for an alternative to austerity, too: to invest, rather than rolling back the state. The same goes for English for Speakers of Other Languages (Esol). Being able to speak English is good for immigrants, giving them opportunities they are otherwise denied; and it is good for social integration, too. But the government is slashing Esol funding, while simultaneously both complaining about the failure of immigrants to learn English, and presiding over record levels of immigration. Perverse, to say the least. We desperately need to make the case for properly resourced Esol courses, allowing immigrants to learn English for the benefit of all.

My own preference is to focus on making the case for refugees, particularly given Britain's embarrassing failure in contrast to countries like Germany and Sweden. Economic migration is a fact of life, like the weather. People will always move to find opportunities elsewhere. But the process (as distinct from the consequences) is neither innately a 'good' or 'bad' thing. I suppose I see the debate as rather like 'social mobility': the idea that we simply scoop up a small minority of deserving individuals from the poorest reaches of society and parachute them into the middle-classes. The real focus must surely be on reducing inequalities: and that has to be our approach globally, too.

The ideas offered here are insufficient. It is a plea for a debate. The left has failed, and failed badly, in the debate on immigration. We're not even in the ring anymore. Our failure to build a convincing, compelling argument on immigration poses an existential threat to our movement. We are losing the hearing of millions of working-class people. It is time we did something about it.