As a result, across the country many families stand to face two inheritance tax bills in relatively quick succession and need to plan accordingly.
The silent threat
To solve this problem, we need to understand why many families may not realise they are affected. The reason for this potential IHT spike is largely due to the record rises in house prices - which has drastically increased the number of individuals liable.
Overall, the average cost of a house has increased 34 per cent since 2009. There is also the value of other assets individuals may own.
Take the FTSE 100, which opened in 2009 at 4,434 and at the time of writing is at 7,414, an increase of more than 67 per cent.
Individuals with even a relatively small portfolio of stock market investments may not realise that, combined with their other assets, they are above the IHT threshold.
The true impact of this asset boom is very clear when we look at property prices across the country. In some postcodes in London, as many as 93 per cent of properties are over the IHT threshold; even at the lower end it is still more than 63 per cent.
Looking at the UK as a whole, 28 per cent of postcode areas have seen the number of property sales exceeding the IHT threshold double in the past six years.
These include: Brighton, Bromley, Bristol, Cambridge, Colchester, Croydon, Durham, Northampton, Norwich, Portsmouth, Stevenage, Tweed, Uxbridge, and Watford.
For consumers, this is a major area of education. There is a lot of misunderstanding among even informed consumers about what an individual's IHT allowance is.
Many people believe that a couple's joint allowance is £1m. In fact, it will only reach that in 2020. Many do not realise that these allowances are dependent on owning or having owned a property, so if the majority of wealth is in other assets, such as stocks and shares, individuals may be liable for more than they think.
There is also a lack of understanding that these allowances can only be transferred to a spouse or partner, and that they only apply if the estate is inherited by a direct descendant.
This crucially means those who would like to leave their estate to people other than their children, will lose out on any IHT property relief.
Tapered property allowance.
In addition some people may not realise that the property allowance is also tapered for estates worth more than £2m - reducing a couples IHT free £1m by £1 for every £2 over the threshold.
Managing this complex market needs much more education and new solutions to help advisers and their clients.
