PoliticsHome has published a YouGov poll in 238 marginal constituencies. It shows that the Conservatives are heading for a massive majority, as they take seats off both Labour and the LibDems. The poll was actually carried out in late July but more than 37,500 voter interviews were carried out, which makes it the largest of its kind. According to the poll the Conservatives would end up on 398 seats with Labour on 160 and the LibDems down to 44.
However, ComRes has a poll for the Independent on Sunday with the Conservatives down to 39% with Labour on 27% and the LibDems on 21%. This is the second poll in a row which shows the LibDems at 20% or over, and their rise in support is entirely at the expense of the Conservatives. There is an obvious conclusion to be drawn: Conservative inclined voters like the LibDem message on tax cuts. There's a simple way for the Conservatives to reverse this minor haemmorage in support.
Anyway, back to the marginals poll. It really is incredibly comprehensive. Anthony Wells of UK Polling Report explains HERE how it was conducted. You can download the 34 page report HERE. There are individual consituency reports available, but you have to pay for those - although rather unhelpfully it doesn't say how much.