Two large polls, one by Survation (15,029) and one by YouGov (18,761), and both using the highly regarded, for its accuracy, multilevel regression and post-stratification (MRP) process predict a Tory wipeout at the next General Election.
Labour could get between 403 to 458 seats and Conservatives only 98 to 155 seats. The SNP would fail to be the largest party in Scotland by some way and the LibDems could get something like 40 to 60 seats.
Landslides like those predicted are not good for democracy IMHO but unfortunately the pollsters do not provide overall percentages for the parties so we cannot tell what the results might be under PR V FPTP.