The number of estates in the UK paying inheritance tax rose by 72% in the five years up to 2004, according to a study.
There has been a rise in the number of inheritance tax cases
An increase in property prices left about 30,451 estates - most worth less than £500,000 - liable for the tax.
A further 22% rise to 37,000 is expected by 2007, according to Halifax, which carried out the study.
It is calling for the inheritance tax threshold to be raised, saying it would be set at £430,000 if it had increased in line with house price inflation.
The threshold for inheritance tax has risen by 85% since 1996 - but the housing market has grown by 179%.
The threshold is set at £285,000 - but the government intends to further increase it to £325,000 by 2010.
Halifax group economist Tim Crawford said: "The steep increase in the number of estates paying inheritance tax highlights that the current inheritance tax threshold of £285,000 is too low.
"Significantly, families with lower valued estates are paying an increased share of the total inheritance tax take whilst the super-rich are paying a smaller share."
A Treasury spokesman said 94% of estates would pay "no inheritance tax whatsoever" as a result of the government's planned adjustment of the threshold.
Inheritance tax is expected to pull in revenue of £3.6bn this financial year.
Have you been liable for inheritance tax? Send us your experiences using the form below.
The following comments reflect the balance of opinion we have received:
Not only is the present threshold outrageous, but the very notion of having to pay an inheritance tax at all is nothing short of theft on the part of the government. What business is it of Gordon Brown and co at all that when a senior member of a family passes away, their sons and daughters are forced to PAY for the privilege of inheriting money and property which is intended for them alone, and which the deceased usually has indicated with a will. This is an abominable intrusion at the time of a loss of a parent.
Stuart McConnell, Colchester UK
My Dad died five years ago and left his house and two flats to his four children. We were each subject to the tax and I find it completely unfair. He was an ordinary working man and had already paid tax on the earned income he used to buy his property - we are not talking a huge sum here, yet we were staggered by just how much the taxman wanted from us.
Mal Adams, North Shields, UK
I am dismayed that the super-rich are still let off the hook when it comes to paying their fair share. However, having inherited recently from my late mother, I do believe that inheritance tax is one of the fairest and most painless ways of funding nationally-shared expenses.
Susan, Berkshire, UK
Taxed when you earn it, taxed when you save it, taxed when you die. Is it any wonder that so many people adopt the "spend, spend, spend" mentality when all you get for your prudence is more tax?
Huge, Bedford, UK
It is quite right that better off pay taxes. My parents' wealth came from their efforts, not mine. There is no reason why my kids should inherit untaxed my wealth through no effort of their own. I would however move to taxing bequests over a certain value - say £100k - rather than estate values.
Patrick Hearn, Somerset
When my father died a year ago, his estate became liable for inheritance tax after a life insurance policy of his paid out, pushing his total estate value to just over the tax threshold. My personal opinion is that this tax is nothing short of theft - the government feel that they can 'steal' this money, despite the deceased person having already paid tax on it. In effect, this money is taxed twice, which is extremely unfair and very upsetting to many people, especially as they will already be going through a very sad time.
Richard Atkinson, Godalming, UK