In a May 2004 poll, 45% of voters said they would vote to leave the EU in such as poll as against 43% who would vote to remain. Support for withdrawal rises to 51% if the continuance of trade with the EU could be assured (as it would have to be under World Trade Organization rules). This is in line with a number of previous similar polls. 60% favour leaving the EU if the alternative is joining the euro.
[Source: YouGov Poll, 14 May 2004]