David Cameron’s negotiations with the EU and the 23 June referendum were designed to woo UKIP voters back to the Conservative Party. However the concessions he has won are relatively minor; instead he has infuriated large numbers of Tory MPs and deepened the division in his own party.

As the Financial Times put it: “Eurosceptics would have preferred the prime minister to be ‘battling hard’ over the repatriation of EU employment law, scrapping the Common Agricultural Policy or asserting British supremacy over EU law, not child benefit payments for Polish plasterers.”

“Repatriation of EU employment law” here means enabling the British government to scrap the laws deriving from EU rules which limit working hours, give rights to agency workers, require consultation on redundancies, and protect earnings when a job is transferred from one contractor to another. That’s what right-wing Tories and Ukip want, as well taking rights away from EU-origin people now working in Britain, and making it more difficult for workers to move across borders to get better jobs.

Cameron couldn’t get that, and settled for mean-spirited and reactionary — but, in the large picture, minor — benefit cuts. Thus the Daily Mail has claimed that 140 Tory MPs now publicly support leaving. Nearly 100 still have to declare. Seven Cabinet members, including Michael Gove, Iain Duncan Smith, and the shameless opportunist Boris Johnson, have declared for Brexit. Most of big business oppose Brexit because they think (rightly) that it might disrupt flows of investment, trade, and labour. Maybe not much, since a capitalist Britain out of the EU would probably try to negotiate a deal similar to Norway and Switzerland, which apply almost all EU regulations without having a say in them, but it might disrupt.

As socialists, our concern is not what is “good for business”. Solidarity is for a vote to remain in Europe for the exact opposite reason that the Tory right and Ukip are for Brexit. We support workers’ rights and open borders. We dislike the existing EU regime because we want more workers’ rights, and more open borders, than it includes. The Tory right and Ukip want to use Brexit as a springboard to turn Britain into a minimal-workers’-rights, low-regulation, low-wage, low-social-provision, offshore site for the multinationals. We want to use a vote to stay in as a springboard for greater unity and solidarity of workers across Europe to win more workers’ rights, more open borders, more social levelling-up, more migrant rights.

The Labour Party is officially committed to campaigning for an in vote, and only a few Labour MPs are lining up with Ukip and the Tory right. Jeremy Corbyn responded to Cameron: “The prime minister has been negotiating for the wrong goals in the wrong way for the wrong reasons.

“He should have been talking to other European leaders about action to save our steel industry; about how to stop the spread of low pay and insecure jobs, and end the undercutting of wage rates and industry-wide agreements through the exploitation of migrant workers. He should have been focused on the scandal of the refugee camps in Calais and Dunkirk and how to deal with Europe’s migration crisis in an equitable way.

“He could have been using Britain’s leverage to stop the threat to our services and rights in the secretive Transatlantic Trade and Investment Partnership (TTIP) negotiations; to build human rights and environmental protection into future trade treaties; and halt the pressure from Brussels to deregulate and privatise public services. He could have been arguing for an end to self-defeating austerity and for the strengthening of workers’ rights across Europe….

“Cameron’s Tories want a free-market corporate Europe. We want a social Europe of decent jobs and equality for all.”

That was more promising than the so-far uninspiring official “Labour In for Britain” campaign, run by right-winger Alan Johnson.

The “Brexit” camp includes much of the Tory Party (and the worst parts of it); Ukip; forces to the right of Ukip; and charlatans such as George Galloway. Yet the SWP, Socialist Party and CP-backed Morning Star newspaper think they can build a “left-wing” campaign to leave the EU.

There are many faults with the EU: we will vote “in” to get a better basis for a fight for democracy across Europe, not because we like the present undemocratic structures. But how can building higher barriers between countries improve the prospects for working-class cooperation and joint industrial and political effort at the European level?

It can’t, particularly in a climate where a major plank of the “leave” rhetoric is anti-migrant. The bosses are uniting across Europe. So must we! We should not seek to retreat to the situation that prevailed before European integration: competing and often warring capitalist states. A really “left-wing” leave campaign is impossible where the “leave” camp is dominated by Little Englanders and xenophobic migrant-bashing or scapegoating.

We support the campaigns Another Europe Is Possible and Workers’ Europe. The Workers’ Europe Facebook page and blog provide campaigning resources, including up-to-date articles and comment, and model motions to put to your union/Labour Party branch or student union, supporting these vital ideas: • Vote against UK withdrawal from the EU • Defend migrants’ rights and oppose racism • Campaign for a workers’ Europe based on solidarity between working people.

Cameron's EU deal

What Cameron demanded from the negotiations and what he got:

1. He wanted a freeze to EU migrants’ in-work benefits, e.g. tax credits and housing benefit. What he got: If it wants and if it meets certain criteria, the UK can in future apply an “emergency brake”. This would mean EU migrants working in the UK would not be eligible to the same benefits as other workers, for up to four years. Cameron conceded that the changes would not apply to EU workers already in the UK, only to new arrivals. Once the brake is applied, these rules can remain in place for seven years only, although repeat applications are allowed.

2. Stopping EU migrant workers sending child benefit to their children living outside the UK. Before the EU summit Cameron stepped back to the demand that child benefit should be indexed to the standard of living in the country where the children live. Cameron got that. It will apply to new arrivals to the UK, once legislation has been passed, and to all workers in the EU from 1 January 2020. Applied now, this would affect 34,000 children of EU migrants working in the UK, and the actual saving to the UK would be just £25m (or maybe nothing, once the extra admin costs are factored in). The measure is nasty and will be financially significant to some families. Its purpose for Cameron is symbolic.

3. Protection for countries outside the eurozone against regulation made by those inside: Cameron won the right of non-eurozone states to force a debate among EU leaders about “problem” eurozone laws. That does not amount to a veto. It only delays matters.

4. Cameron wanted a declaration that the treaty motto of “ever closer union among the peoples of Europe” did not apply to the UK. He got this reassurance: “It is recognised that the UK ... is not committed to further political integration in the European Union... References to ever-closer union do not apply to the UK.”