The comments follow reports that PM David Cameron is planning to fight the next general election on the back of a pledge to raise the IHT threshold to £1m.
Mr Cameron has also recently spoken about how IHT should “only be paid for by the rich.”
Mr Giddens said IHT has become a “big earner” for the Treasury.
However, he warned that the £325,000 tax threshold, set in 2009, was in danger of trapping families and had reduced any incentives for people to keep creating wealth or pass it on to family members.
Research by the firm has revealed that the UK’s IHT regime is the second strictest in the developed world after Ireland – in contrast to the likes of Australia, which has scrapped the tax, or the US, which has much higher thresholds.
Colin Low, managing director of Essex-based Kingsfleet Wealth, said: “An increase in the threshold would be great, but there are other priorities and there are many planning opportunities available to mitigate the tax.”
