By Caroline Lucas

Last year, in the dying days of the EU referendum campaign, I urged fellow progressives to make a positive case for free movement. The Leave campaign's relentless attacks were cutting through, and it felt like we were permanently on the defensive on the issue.  Sadly very few other politicians stepped up to the plate – and the Remain campaign's gamble that economic security would somehow trump years of anti-immigrant rhetoric from the major parties proved to be a woeful miscalculation.

Of course migration wasn't the only issue people were voting on – indeed plenty of evidence suggests that it wasn't the main one – but there’s little doubt that the toxic combination of Daily Mail headlines and governments blaming migrants for the country's problems had an effect on the result. If others had been willing to speak up for freedom of movement, I can't help but think that the result might have been different.

Fast forward to this year's general election and it's a real tragedy to see a similar pattern emerging. The Tories are basing their strategy on reducing migration to economy-wrecking levels and Labour keep repeating that 'free movement will end'. When pressed on the issue Labour politicians volunteer platitudes about the immigration they want to halt, but they hardly go out of there way to make a positive case. Today, alongside former Green Party leader Natalie Bennett, I'm doing what other parties leaders won't – I’m standing up for free movement.

It is important to recognise the fact that many people have worries around migration. At the heart of people's concerns tend to be two major factors: jobs and public services. And it's no wonder that people are angry either, given that wages have stagnated in Britain and our public services are stretched to the point that people are being treated in hospital corridors. But the truth is that such pressures are not caused by free movement. Just last week the London School of Economics released a report which exploded these myths, saying that:

"Immigrants pay more in taxes than they take out in welfare and use of public services…immigrants help to reduce the budget deficit. There is little evidence that immigrants have negative effects on crime, education, health or social housing."

It went on to debunk myths around jobs:

"Neither immigration as a whole nor EU immigration has had significantly large negative effects on employment, wages and wage inequality for the UK-born population."

The summary of the report: almost everything the government has told you about migration simply isn't true.

Of course freedom of movement isn't just good for our economy, it benefits our communities too. Indeed the Green party believes that being able to live, love, work and study across 27 different countries is a wonderful gift – and that people who come here to make a life enrich our society. It seems to me to be a real tragedy that young people will be denied this right – and that both Labour and the Tories are willing to sacrifice our economy by yanking us out of the single market, simply so they can say they will end freedom of movement.

The Green party's policy on freedom of movement is clear: we want to keep it. The simplest way to do this would be to remain a member of the European single market, thus bringing both the benefits of free movement and the positives of being part of the tariff-free trading bloc. But even if Britain is yanked out of the single market, then we want young people especially to be able to enjoy the right to free movement across the continent, and for young people from other countries to be able to come here too. That could be through a reciprocal visa scheme or perhaps the EU could agree that anyone under 25 has same free movement rights as now.

I'm proud that my party has continued to make a case for freedom of movement, and defended migrants against the scorn poured on them. Britain is a country built by migrants – and one with a proud history of welcoming people from across the globe. Closing ourselves off from the rest of the world at this pivotal moment would be a mistake, and our MPs will be using their position in parliament to keep pushing for freedom of movement to be retained for generations to come.

Caroline Lucas is co-leader of the Green party and parliamentary candidate for Brighton Pavilion. Green party members are to stage a dance protest outside the Home Office early this evening against plans to scrap freedom of movement.

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