Gordon Brown dutifully raised the IHT threshold in his recent budget.

But it doesn't take a genius to calculate that the threshold has not kept pace with property price inflation, which means that a rapidly increasing number of people are being caught out by this 'tax on death.'

New research from the Halifax forecasts that by 2020, some 4.2 million households will come into the reach of IHT.

The threshold now stands at £285,000, up from £275,000.

After that amount, a 40% tax on the excess becomes due, unless the estate received by a spouse.

Halifax has calculated that the number of properties in the country that value in excess of the £285,000 threshold is now 1.5 million, amounting to 8% of all owner-occupied properties.

Between 1997 and 2004 the threshold rose by 22%, compared with house price inflation of 129%, according to the Halifax's figures.

In 2005 the threshold went up again, this time by 5% - and the current rise, plus one planned for next year will bring the threshold to £300,000

Still a long way behind property price inflation. In fact, the Halifax calculates that the current rate should be well above £400,000.

A whole new generation of IHT tax payers
The problem is especially pronounced in London and the south east where property prices are higher. Many people who have never been higher rate tax payers during their lifetime, find that after death their estate enters the higher tax band.

Revenue going to the government from IHT more than doubled, the government estimates, between 1996 and 2006, to £3.4 billion.

£5.5 billion by 2020

By 2020, Halifax estimates, the government's IHT take could rise to £5.5 billion in today's money.

That amounts to a 244% rise from the £1.6 billion received by the government in 1996/97, the last time there was a big rise in the IHT threshold.

Property prices have increased by an average 176% in the last 10 years, compared to an 85% increase in the IHT tax free amount.

The IHT tax free limit is projected to rise to £325,000 by 2009/10.

Research by the Council of Mortgage Lending has revealed that some ten years ago, the amount home-owners received from the government (tax relief, income support, etc), exceeded taxes paid on residential property by £2.6 billion.

Now, the situation has reversed and property owners are net contributors to the government of more than £7.5 billion

Property amounts to around 50% of the estates left by people.

So, what can be done to lesson the IHT burden? The answer is: a lot. And you'll find those answers in IHT Property Secrets