A YouGov poll in the Sunday Times gives the following:
Conservative 41% (nc)
Labour 31% (nc)
Liberal Democrat 17% (+2)
Not much to talk about on this. Labour seems to be holding at or around 30%. According to the paper, the outcome would be a tiny Conservative majority. Compare these numbers with the 1997 numbers of 31-43-17 which gave a Labour majority of 164 and you see the impact of a favourable constituency map for Labour.