Royal succession rules banning Roman Catholics from ascending to the throne should be scrapped, the Prime Minister has said.
David Cameron said Catholics should be able to become king or queen, or to marry the heir to the throne, but warned that changing the 1701 Act of Settlement would take time.
Mr Cameron has said he would also like to scrap the law giving precedence to male heirs, which has come under increased pressure with the upcoming royal wedding.
The Prime Minister and his deputy Nick Clegg are in discussions with other Commonwealth leaders about how to secure a change across the nations where the Queen is the monarch.
He said yesterday: "I think it's right to discuss both sets of changes, but I think we have to recognise that the Queen is not only the Queen of the United Kingdom, but also many other jurisdictions as well."
He added: "In principle I think both changes should be made, in principle I'm of that view. But it will take time because it's not just our decision, it's the decision of others as well."
Speaking last week, Mr Clegg said: "If Prince William and Catherine Middleton were to have a baby daughter as their first child, I think most people would think it is perfectly fair that she would eventually become queen. It is worth looking at, but it is complex and will require some careful thought."
King James VII and II, the last Catholic monarch of Britain, was overthrown in 1688.