If only for posterity, I'll stick my neck out and predict Labour as the largest party, but by just a few seats - 290 for Labour vs 280 for the Tories, let's say. It should be enough to combine with the SNP and Lib Dems to form a viable government for long enough to hold a referendum, but once that's done there will probably be another election within a year.
In the spirit of bookending, I'm going to make a second prediction one day before polling day:
Tory: 305
Labour: 257
SNP: 45
LD: 21
DUP: 8
SF: 7
PC: 3
Alliance: 2
UUP: 1
Green: 1
Brexit: 0
Figures above assumed with a +/- 5 seats for Tory/Lab/SNP.
I'm not too fussed about percentages, but something like a
39/
38/
13 is the general ballpark.
A few minor predictions: Johnson, Skinner, Swinson, Baker, Berger, Ummuna, and Redwood win their races. Raab, Goldsmith, Onn, and Blake (LD in Sheffield Hallam) lose theirs.