The latest MORI survey gives the Tories a 3% lead.  This suggests a 5% reduction in Tory support since MORI’s last survey on 19th June.  A very well-publicised MORI survey at the start of the month gave Cameron’s Conservatives a 10% lead.  That survey was bought by The Sun but the last two polls do not appear to have been bought by any newspaper.  The effect of the MORI poll is to drag down the Tory lead in ConservativeHome’s poll of polls by 1% to 3.2%.  Given the volatility of MORI surveys I am beginning to think of excluding them from the PoP.  Does anyone have strong views?  In MORI’s defence this latest survey is in line with last weekend’s ICM survey which also put the Conservatives on 36% (and with only a 1% advantage over Labour).