David Cameron and the Remain camp could probably have done without this morning's immigration statistics - figures that are almost certain to be put centre stage during the last four weeks of the referendum campaign.
The numbers, published by the Office for National Statistics (ONS), showed net migration was running at 330,000 in 2015, as a record number of people came to the UK from the European Union while the number of UK citizens packing up for a life abroad dropped.
Boris Johnson, campaigning for Brexit, leapt on the figures almost immediately, blasting EU policy and calling out the prime minister personally for his failure to bring down the level of net migration.
The number of people coming to the UK from the EU - at 270,000 - was a record high as arrivals from Romania and Bulgaria jumped by one-third. The ONS said that 66 per cent of arrivals from the EU were coming to the UK for work-related reasons, with 101,000 holding a definite job offer.
The total number of people who arrived in the UK between January and December 2015 was 630,000, down 0.3 per cent on the year before. Emigration - the number of people leaving - dropped by seven per cent to 297,000.
"The increase in net migration was the result of a decrease in emigration, whereas immigration was at a similar level to the previous year," the ONS said.
Large increase in short term migration to UK. Fall in student numbers— Jonathan Portes (@jdportes) May 26, 2016
"That means we are adding a population the size of Oxford to the UK every year just from EU migration," said Boris Johnson.
"The system has spun out of control. We cannot control the numbers. We cannot control the terms on which people come and how we remove those who abuse our hospitality. This puts huge pressure on schools, hospitals and housing.
"The prime minister's deal has given away control of immigration and asylum forever ... The prime minister repeatedly promised that he would get a grip of this ... the government has failed."
The ins and outs
|Total arrivals||Total departures||Net migration|
|UK citizens||83,000||123,000||minus 39,000|
The ONS cautioned that none of the headline figures were "statistically significant".
In total, just under half of all new arrivals came to the UK for work - a record high in absolute terms - a quarter came for study, and 12 per cent came to join relatives.
John Hawksworth, chief economist at PwC, said the figures "reflect the strength of the UK jobs market last year, pulling in more workers from across the EU and beyond".
Business groups, already flustered at what they see as a broken migration system, worried that the numbers, combined with the debate around the EU referendum, were a cause for concern.
"Employment is at a record high, and there are big skills gaps that employers cannot fill domestically. Despite the overblown rhetoric that today’s figures have sparked ... It is important to take a step back and remind ourselves immigration is a much broader question than just the EU referendum. " said Seamus Nevin of the Institute of Directors (IoD).
Mark Hilton, immigration director at London First, added: "These figures show that Britain is a magnet for talent and investment. Business is worried that the anti-immigration rhetoric in recent weeks will encourage the government to pursue even stronger anti-immigration policies after the referendum. This would not be in the interests of London, which thrives exactly because it is a global city."
Even without the referendum campaign, migration has been a sticky subject for the Conservatives, who are officially targeting net migration in the "tens of thousands".
Today's figure, up 20,000 on last year, is more than three times that amount, and shows no sign of coming down soon.