This is the proposal of the Conservative policy group headed by ex-cabinet minister John Redwood as reported by the BBC
I do not think this is the first time such a proposal has been made by a Tory policy group and is unlikely to be the last. It is interesting to note that the shadow Chancellor comments: ""I've got to make sure that we can afford it, that the country can afford it, that it is consistent with economic stability, that it's part of a coherent economic programme. "
I think this is the crux of the matter. IHT currently brings into the exchequer about £3.5 billion per year and is set to rise at least in line with asset prices over the coming years. If Inheritance tax was abolished then the Treasury would seek to replace the tax from somewhere else which will almost definately be as politically unpopular especially if Labour use the "robbing the poor (new taxes) to pay the rich (abolishing IHT ) " card.
For what it's worth, I anticipate that the Conservatives will go into the next election with a long-term aim of abolishing IHT but with a plan to raise the threshold above current levels proposed in the short term or even by reducing the initial rate of IHT due to say 20% on smaller taxable estates.
One way or another I suspect IHT will be a "hot political potato" at the next general election.