Arguably, immigration was at the heart of the referendum campaign in 2016.
David Cameron's decision to have a vote on EU membership came after years of pressure on parties to deal with what was regarded as an 'influx' of EU immigrants, especially from Eastern European accession countries.
The UK was one of three countries which opened its borders straight away to workers from the new member states.
With this election fuelled by the Brexit crisis, it's no surprise that immigration policy remains high on the campaign agenda.
Being 'soft' on immigration is seen as a vote loser. Today, the Conservative Home Secretary Priti Patel announced that a Tory government will reduce "immigration overall" to the UK.
"We will reduce immigration overall while being more open and flexible to the highly skilled people we need, such as scientists and doctors," she said.
"This can only happen if people vote for a Conservative majority government so we can leave the EU with a deal.
She claimed there would be a "surge" in immigration under a Labour government, which would put a huge strain on the NHS and other public services.
That's a different approach to previous government commitments.
Promises made, when Theresa May was Home Secretary, to reduce net migration to the "tens of thousands" were never kept.
Labour says previous Conservative governments have tried to sound tough but failed to hit their own targets.
Deal or No-Deal, after Brexit the Conservatives say they'd scrap freedom of movement (a condition of EU membership).
A new system of immigration is only a set of proposals at the moment but ministers say it will be designed along the Australian "points based" system.
Despite proposing the largest overhaul of immigration policy for almost 50 years, the Tories only have rhetorical arguments with no hard and fast policies for voters to look at at this stage.
Labour is also deciding precisely what its policies will be.
At its autumn conference, delegates passed a motion aimed at a radical shake-up of the whole system.
Activists wanted to end the so-called 'hostile environment' immigration policies.
The free-movement motion approved by Labour delegates included a commitment to close all migrant detention centres; abolition of the “no recourse to public funds” legislation that prevents migrants from accessing many services; a move to “maintain and extend free movement rights”; and rejection of “any immigration system based on incomes, migrants’ utility to business, and number caps/targets”.
However, Labour's leadership has yet to announce how much of this agenda would become government policy.
The Tories say these proposals would increase net migration by 840,000 a year.
The Liberal Democrats Home Affairs spokeswoman Christine Jardine said today: “Patel’s comments this morning show that the Tories only care about arbitrarily reducing immigration numbers with no regard for the consequences.
"Our public services, including our NHS, rely on the contribution that immigrants make. But the Tories are willing to put this at risk just to pursue a nationalist Trumpian agenda."
Meanwhile, the SNP says the Tories and Labour are "threatening Scotland's economy and public services" with their damaging hostile immigration policies.
SNP Immigration spokesperson Stuart McDonald said: “A Scotland-specific migration policy will allow us to prioritise what our economy and society needs – rather than having to abide by wreckless Tory and Labour plans that could cost our economy £10 billion a year.
“The SNP will not stand for Westminster's damaging policies and the demonisation of migrants."
According to Full Fact, a fact checking charity, "an estimated 202,000 citizens from other EU countries immigrated to the UK in the year to September 2018, and about 145,000 emigrated abroad. So EU ‘net migration’ was around 57,000 — roughly the lowest level recorded since 2009."
It adds: "In the year before the referendum, net EU migration was estimated at 189,000, so there’s been a large fall following the vote.
"Estimated non-EU net migration, meanwhile, is 261,000 a year — the highest level recorded since 2004. It has been almost consistently higher than EU migration for decades."
Immigration statistics have always been a subject of much argument.
Until the party manifestos are published it is also difficult to accurately describe different policies at this stage of this election.