More than half of Brits would vote to remain in the EU, the latest ITV News/ComRes poll suggests - but the 'Leave' campaign has gained some ground.
The survey of 1,000 British adults aged over 19 found that 52% of adults would vote with the 'Remain' campaign, while 41% - slightly higher than last month's figure - would vote to leave.
In a straight in/out vote, experts say this would see Remain defeat Leave 57% to 43%.
The economy is by far the most important issue for voters with 55% saying it was the main factor influencing their decision.
And women are significantly more likely to vote to stay than men (51% to 44%), the survey showed.
Immigration was the second most important issue affecting the British public with 51% saying they were concerned over the number of EU migrants entering the country.
This was followed by control over Britain's laws (47%) and national security (42%).
Other factors included the ability of UK and EU citizens to live and work abroad (27%), British influence on the global stage (21%), Benefits for EU migrants (18%) and the uncertainty of leaving the EU (18%).
But despite David Cameron's warning that leaving the EU could risk war, the vast majority (85%) believe it would make no difference.
Three in five Brits (62%) also think the three million people coming into the UK in the next 14 years, as predicted by the Treasury to project the economic impact of a Brexit, is "too high".
Meanwhile, just under seven in 10 (69%) think it would increase pressure on the NHS and other public services.
And around half think that Albania, Macedonia, Montenegro, Serbia and Turkey joining the EU would make it less secure (47%) and worse off (48%).