UK pollsters got it wrong because no one wants to admit they're voting for Tories
The British Polling Council is about to carry out an enquiry as to how the pollsters could have so wrongly forecast the outcome of the British general election: there was David Cameron writing his resignation speech in preparation for a hung parliament and a constitutional crisis (and Samantha Cameron allegedly packing up the kitchenware to move from No 10) when came the stunning surprise: the vote produced a Tory majority government, and the lowest Labour support since 1983!
I think I can help out the British Polling Council's investigation into itself: and no algorithms or psephological forensics are required.
The truth is, a person of functioning sanity would no more admit to voting Tory at a north London dinner party than an individual with a normal instinct for self-preservation would disclose that he was a practising Catholic - who even sought to send his child to a Catholic school, the extremist! - at a soiree in Dublin 4.