A second opinion poll within a week has suggested that a more of the public are currently minded to vote to leave the European Union than stay in this month’s referendum.

The Observer/Opinium poll put support for Brexit on 43 per cent, while 40 per cent said they intended to vote to keep the UK in the union. The rest were undecided.

The poll suggests the remain camp has lost four percentage points in the last two weeks, during which period Boris Johnson and Michael Gove have relentlessly campaigned on immigration.

What has the EU ever done for us? Show all 7 1 /7 What has the EU ever done for us? What has the EU ever done for us? 1. It gives you freedom to live, work and retire anywhere in Europe As a member of the EU, UK citizens benefit from freedom of movement across the continent. Considered one of the so-called four pillars of the European Union, this freedom allows all EU citizens to live, work and travel in other member states. What has the EU ever done for us? 2. It sustains millions of jobs A report by the Centre for Economics and Business Research, released in October 2015, suggested 3.1 million British jobs were linked to the UK’s exports to the EU. What has the EU ever done for us? 3. Your holiday is much easier - and safer Freedom to travel is one of the most exercised benefits of EU membership, with Britons having made 31 million visits to the EU in 2014 alone. But a lot of the benefits of being an EU citizen are either taken for granted or go unnoticed. What has the EU ever done for us? 4. It means you're less likely to get ripped off Consumer protection is a key benefit of the EU’s single market, and ensures members of the British public receive equal consumer rights when shopping anywhere in Europe. What has the EU ever done for us? 5. It offers greater protection from terrorists, paedophiles, people traffickers and cyber-crime Another example of a lesser-known advantage of EU membership is the benefit of cross-country coordination and cooperation in the fight against crime. What has the EU ever done for us? 6. Our businesses depend on it According to 71% of all members of the Confederation of British Influence (CBI), and 67 per cent of small and medium-sized enterprises (SMEs), the EU has had an overall positive impact on their business. What has the EU ever done for us? 7. We have greater influence Robin Niblett, Director of think-tank Chatham House, stated in a report published last year: “For a mid-sized country like the UK, which will never again be economically dominant either globally or regionally, and whose diplomatic and military resources are declining in relative terms, being a major player in a strong regional institution can offer a critical lever for international influence.

It follows two similar polls by YouGov earlier this week – both of which showed growing support for the leave campaign.

Tellingly two in five voters (41 per cent) now cite immigration as one of their two most important issues when deciding how to vote. Just over a third (35 per cent) cite Britain’s ability to make its own laws without EU interference and 29 per cent cite the impact of leaving on the UK economy.

Half of the 2,007 people surveyed said they believed that immigration would be under better control if the UK did leave the EU. Twelve percent felt that the UK would have more control if the country retained its EU membership, and 24 per cent said there would be little difference.

Opinium said a move to leave had also been reflected in answers to their so-called “nudge” question, which asks those who do not yet know how they will vote in what direction they are leaning.

In the last Opinium survey two weeks ago, those split 55 per cent leaning to remain and 32 per cent leaning towards leave.

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In the latest survey, the gap has narrowed dramatically, with 36 per cent leaning towards remain and 33 per cent towards leave, even when the methodological updates were implemented.