Two elderly British sisters have lost their case in the European Court of Human Rights to allow them to avoid inheritance tax when one of them dies.

They argued that British law treats them less favourably than a lesbian couple in a civil partnership.

The siblings have been living together in Wiltshire since they were born, but Joyce, 88, and Sybil Burden, 90, fear that one of them will be left with a large inheritance tax bill when the other passes away.

In a 15-2 vote, judges sitting in Strasbourg ruled they did are not the victims of discrimination. “The absence of such a legally-binding agreement between the applicants (the Burdens) rendered their relationship of co-habitation, despite its long duration, fundamentally different to that of a married or civil partnership couple.”

The sisters vowed to continue their fight through lobbying politicans. “We are struggling to understand why two single sisters in their old age, whose only crime was to choose to stay single and look after their parents and aunts, should find themselves in such a position in the UK in the 21st Century.

“Having always paid our taxes and cared for our relatives and each other when necessary without any help from the state, we are now in the worrying and unsettling position of being unable to secure each other in our last few years.

“It is not an exaggeration that we feel as if we have been personally persecuted. This is a day we hoped, as British citizens, we would never see.”

They have been arguing that they should be treated in the same way as a married couple since 1976.

In 2005 the implementation of the Civil Partnership Act brought inheritance laws for gay couples in line with those of married couples, meaning a surviving spouse will inherit their partner’s estate without paying tax.

The law does not apply to family members living together, which Joan and Sybil claim is a contravention of their human rights.

In December the European Court of Human Rights rejected the pleas of the elderly sisters asking for the same inheritance tax rights as married and gay couples by four votes to three.

The spinster sisters 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.

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.