The Ft analysis of all polling on the Euro elections says Tory vote will collapse to Farage ( half of those who voted Tory in 2017 will vote for Farage. 1 in 8 will support a remain party) leaving the Tories with 14%. Worst previous performance for a governing party was 15% for Labour under Brown.
Labour will lose 28% of its 2017 vote to remain parties and 13% to UKIP or Brexit party. Likely total vote 25%. Farage to come top with 29%. Remain parties will get 29% between them.
I have voted Green ( postal vote)