Opinium/Observer poll: Tory EU referendum voters are switching to remain

As reported in the Guardian, Opinium/Observer poll puts remain four points ahead on 44%, with leave on 40% and 14% undecided. At the beginning of April, leave had a four-point lead.

Opinium poll shows 48% of Tory voters want to stay in Britain, up from 39%, with the Remain now having a four-point overall lead. This is a considerable turnaround since the first Opinium/Observer referendum poll in early April, which showed 44% of Conservative voters in favour of leaving against 39% who backed staying in.