Hanging on the telephone

Just a few days after thinking Labour can secure a majority in England and Wales alone, along comes a Guardian/ICM poll which puts the Tories into a six-point lead, potentially enough to secure David Cameron without the hassle of a coalition (although with the hassle of truculent backbenchers wishing to exert maximum leverage from a wafer-thin majority).  It certainly is in contrast to a slew of other polls putting Labour in the lead and even the pollsters themselves admit that the sample "may be a touch too Tory" and "within the margin of error, but only just."  Then the critical factor emerges - it was a phone interview.
Bob Worcester, the veteran pollster, was wariest of all of write-in polls ('voodoo polls' in his words) but telephone polling wasn't far behind.  Invariably, such call outs will be done to those who possess landlines i.e. have listed numbers unlike mobiles.  And those who possess a landline phone (these days) and are at home when called tend to be the well-off and pensioners, both groups more likely to vote for right-wing stability, in the British case in the form of the Conservative Party.  Though an outlier, conversely it may act as a self-fulfilling prophecy, galvanising the Tory grassroots troops and demoralising the Labour side, such is the fragility of the new normal in British politics.