In its final survey, Opinium said after talking to 3,000 people the referendum was a 'statistical dead heat' with Leave on 45 per cent and Remain on 44 per cent - meaning after taking margin of error into account it was impossible to pick a winner

Opinium's surveys during June have showed a small overall drift toward Leave as undecided voters made up their minds but the pollster said the race was still too close to call