Ipsos MORI/Reuters - 37/37/15

Ipsos MORI's political monitor for September is out and has topline figures of CON 37%(-3), LAB 37%(-1), LDEM 15%(+1). Changes are from MORI's July political monitor - there does not appear to have been one in August.

This is the second poll to show the parties equal after ICM's last month. YouGov earlier this week showed the two main parties within one point of each other. YouGov's voting intention this morning meanwhile was CON 42%, LAB 39%, LDEM 12%.

Something interesting for the methodology geeks amongst us - below is a graph of past vote recall for the 2010 election from MORI's five polls since the general election. Unlike most other pollsters do not weight by past vote, so while we should expect their past vote recall to be more volatile than other companies, any trends that are there will not be weighted out of existance - note the percentage of those saying they voted who say they voted Liberal Democrat. In May, 28% of people telling MORI they voted at the election said they voted Lib Dem, clearly higher than the Liberal Democrats actually got. In the months since then, the proportion of people claiming they voted Lib Dem at the 2010 election has dropped to 21%. We've gone from people claiming they voted Lib Dem when they probably didn't, to people conveniently "forgetting" that they ever voted Lib Dem.