As per a new law providing equal rights to female heirs, a first-born daughter of royal couple, Prince William and the Duchess of Cambridge, Kate Middleton, will be allowed to inherit one of the wealthiest estates in Britain.

This new law, SovereignGrant Bill, which revolutionizes the entire way the royal family allocates funds and manages inheritances, was passed last week by the House of the Lords.

As per the ninth clause, if the first-born of the newly-married royal couple is a girl, she will be entitled to the same rights as a male heir, including the inheritance of the $700 million Duchy of Cornwall.

The new step reflects the process of modernization of the British monarchy system.

Express.co.UK reported that although the Deputy Prime Minister and Lib. Dem. leader Nick Clegg wanted to change the law, Tory Prime Minister David Cameron had said it was not a priority, particularly with the world in financial crisis.

The Duchy of Cornwall covers huge swathes of land in 23 counties mainly across south-west England and is valued at £712 million. The estate provides an annual income of almost £18 million to Prince Charles, as the Prince of Wales and Duke of Cornwall. This, in fact, dwarfs the Queen's income from the Duchy of Lancaster, which is valued at 17.762 million pounds.