Her Majesty's Revenue & Customs (HMRC) claimed back almost £90m last year by challenging the inheritance tax (IHT) valuations on the property of people who died, figures show.
A freedom of information request from accountants UHY Hacker Young revealed HMRC assessed more than 10,000 valuations in 2011 and gained an average of more than £27,000 in extra tax on each case.
The average the previous year was £24,600 a case, the Financial Times reports.
HMRC said challenging property valuations for IHT purposes has always been part of its work, and a spokesman for UHY said HMRC was under pressure to maximise revenues.
"For a bereaved family, it is unwelcome news to hear that HMRC wants to challenge your valuation of the estate and take even more of it in IHT," Mark Giddens, partner, said.
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Spent two years at Sanlam
Will also assess FCA's actions