HMRC has forced families to stump up an extra £1.36billion following investigations into underpaid inheritance tax over the past five years, new figures show.

Suspected errors, omissions or under-valuations of assets can prompt deeper scrutiny of an estate and lead to higher bills as well as interest on late payments and penalties.

'HMRC has substantial investigative powers and will check a range of sources to build a picture of the deceased individual’s financial affairs,' warns NFU Mutual, which obtained the figures on the money recovered via a Freedom of Information request.

The total inheritance tax collected reached a record of nearly £8.5billion in the last tax year – but the arrival of Andy Burnham as Prime Minister has led to speculation about an overhaul which would hit more estates.

Burnham has previously floated the idea of a 10 per cent 'death tax' on all estates to fund the social care system.