The Leave campaign has taken the lead by a single percentage point in the final poll by the Opinium firm to be released before the EU referendum.
Opinium, which was the most accurate pollster at the 2015 general election, said the race was "too close to call" on account of the survey.
The result represents a gain of one point for Leave, who are up to 45 per cent. Remain were on 44 per cent in the survey.
All the changes compared to the firm's penultimate poll are within the margin of error.
That survey, released on Sunday, had Leave and Remain tied on 44 per cent.
A spokesperson for the firm said: "Too close to call in final EU referendum poll. Everything rests on 9 per cent still undecided."
Two more opinion polls, from YouGov and ComRes, are expected this evening.
The Ipsos MORI firm is exected to release a poll at 10am tomorrow.
YouGov will also release a so-called "re-contact survey" where it polls people on how they voted once polls close.
This method is not a full exit poll but should give some indication of turnout.
The European Union referendum takes place on Thursday (UK time). The deadline to register to vote has already passed.
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