Two octogenarian sisters are taking the British government to the European Court of Human Rights over a tax dispute..

Since the introduction of civil partnerships earlier this year, gay and lesbian couples are now exempted from paying inheritance tax when their partner dies, the same exemption enjoyed by married couples.

Religious critics of civil partnerships attempted to undermine the spirit of the legislation by insisting that any two people, including family members such as two sisters, should be able to contract partnerships to take advantage of the tax incentives.

The partnership law excludes family members from contracting a civil partnership.

The spinster Burden sisters Joyce, 88, and Sybil, 81, have written to the Chancellor before every Budget since 1976 asking for exemption for family members from inheritance tax.

Last year they also wrote to the European Court of Human Rights, and were shocked when the court agreed to hear their case.

The sisters are worried that when one of them dies, the 40% inheritance tax on their family farm would mean the remaining sibling would have to sell the property to pay the bill.

Their four bedroom house and 30-acre farm, near Marlborough in Wiltshire, are estimated to be worth £875,000. Only properties worth more than £285,000 are subject to inheritance tax.

Sybil Burden told The Times : “We are looked down upon for being single. We just want to be treated as equal citizens and given the rights we deserve. We’ve saved the Government thousands by caring for our elderly sick relatives till they passed away and have never claimed a penny apart from the pension.”

The case was due to be heard in Strasbourg in July, but was postponed because the British government were not ready to defend their case.

Joyce was cynical about the delay: “They’re just hoping we die before we get to court. But they don’t know how determined we are to see this through.”