Source http://electoralcalculus.co.uk/homepage.html based on 650 seats
Most polls published in September were conducted before the Labour party conference and re-election of Jeremy Corbyn, so it is too early to tell what effect that might have. But the polls were mostly taken after the election of Diane James as new UKIP leader, and UKIP have shown an increase this month, mostly at the expense of the Conservatives and the Liberal Democrats.
The most recent polls from the four pollsters who published polls in August are:
Ipsos-MORI (Evening Standard) has Con 40, Lab 34, Lib 6, UKIP 9, Green 5 BMG has Con 39, Lab 28, Lib 8, UKIP 13, Green 5 ICM (Sun on Sunday) has Con 41, Lab 26, Lib 8, UKIP 14, Green 4 YouGov (Times) has Con 39, Lab 30, Lib 8, UKIP 13, Green 3
The averages: Con 41 (-1), Lab 28 (nc), Lib 8 (-1), UKIP 13 (+2), Grn 4 (nc).
The new national prediction is that the Conservatives will have a majority of 80 seats, winning 365 seats (-10 seats since 4 September).
Link to historical >>> Forecasts, predictions & projections from the past year