The Act of Settlement (1701) laid down that only Protestant heirs of Princess Sophia, granddaughter of James I, may succeed to the British throne. Neither Roman Catholics, nor those who marry a Roman Catholic, nor those born out of wedlock, may remain in the line of succession. Under current common law the crown is passed on by male primogeniture under which younger sons succeed before their elder sisters. See Line of Succession FAQs

On 28 October 2011 the Leaders of the Commonwealth Realms agreed to work to change the succession laws so that descendants of the Prince of Wales will be able to marry a Roman Catholic and remain in the line of successsion, and the right of male primogeniture will no longer apply. It means that if the Duke and Duchess of Cambridge have a first born daughter she will become Queen and any younger brothers will not take precedence. Their first born child will become 3rd in line to the throne. As well as approval by each of the 16 countries which make up the Commonwealth Realms, the changes to the law governing the Line of Succession require ammendments to some of Britain's key constitutional documents, including the Bill of Rights and Coronation Oath Act of 1688, the 1701 Act of Settlement and the 1707 Act of Union between Scotland and England.

The Succession to the Crown Bill 2013 is currently before Parliament, and passed the third reading on 22 April 2013. As both Houses have agreed on the text of the Bill it now waits for the final stage of Royal Assent when the Bill will become an Act of Parliament. The birth of the Duke and Duchess of Cambridge's first child is expected in July 2013, however should the baby be female she would under existing law be next in line after her father and the application of the new Bill would only arise on the birth of a younger brother.

This change will not apply retrospectively to the current line of succession which is given below:

1. HRH Prince Charles, The Prince of Wales (b. 1948)
2. HRH Prince William of Wales, The Duke of Cambridge (b. 1982)
3. HRH Prince Henry of Wales (b. 1984)
4. HRH Prince Andrew, The Duke of York (b. 1960)
5. HRH Princess Beatrice of York (b. 1988)
6. HRH Princess Eugenie of York (b. 1990)
7. HRH Prince Edward (b. 1964)
8. James, Viscount Severn (b. 2007)
9. Lady Louise Windsor (b. 2003)
10. HRH Princess Anne, Princess Royal (b. 1950)
11. Peter Phillips (b. 1977)
12. Savannah Phillips (b. 2010)
13. Isla Phillips (b. 2012)
14. Zara Tindall (Phillips) (b. 1981)
15. David Armstrong-Jones, Viscount Linley (b. 1961)
16. Hon. Charles Armstrong Jones (b. 1999)
17. Margarita Armstrong-Jones (b. 2002)
18. Lady Sarah Chatto (b. 1964)
19. Samuel Chatto (b. 1996)
20. Arthur Chatto (b. 1999)
21. HRH Prince Richard, Duke of Gloucester (b. 1944)
22. Alexander Windsor, Earl of Ulster (b. 1974)
23. Xan Windsor, Lord Culloden (b. 2007)
24. Lady Cosima Windsor (b. 2010)
25. Lady Davina Lewis (b. 1977)
26. Tane Mahuta Lewis (b. 2012)
27. Senna Lewis (b. 2010)
28. Lady Rose Gilman (b. 1980)
29. Lyla Gilman (b. 2010)
30. HRH Prince Edward, Duke of Kent (b. 1935)
George Windsor, Earl of St. Andrews (excluded by marrying a Roman Catholic)
Edward Windsor, Baron Downpatrick (excluded by becoming a Roman Catholic)
Lady Marina Charlotte Windsor (excluded by becoming a Roman Catholic)
31. Lady Amelia Windsor (b. 1995)
Lord Nicholas Windsor (excluded by becoming a Roman Catholic)
Albert Windsor (excluded by becoming a Roman Catholic)
Leopold Windsor (excluded by becoming a Roman Catholic)
32. Lady Helen Taylor (b. 1964)
33. Columbus Taylor (b. 1994)
34. Cassius Taylor (b. 1996)
35. Eloise Taylor (b. 2003)
36. Estella Taylor (b 2004)
Prince Michael of Kent (excluded by marrying a Roman Catholic)
37. Lord Frederick Windsor (b 1979)
38. Lady Gabriella Windsor (b. 1981)
39. HRH Princess Alexandra the Hon. Lady Ogilvy (b. 1936)
40. James Ogilvy (b. 1964)
41. Alexander Ogilvy (b. 1996)
42. Flora Ogilvy (b. 1994)
43. Marina Ogilvy, Mrs Paul Mowatt (b. 1966)
44. Christian Mowatt (b. 1993)
45. Miss Zenouska Mowatt (b. 1990)
46. David Lascelles, 8th Earl of Harewood (b. 1950)
47. Hon. Alexander Lascelles (b. 1980)
48. Hon. Edward Lascelles (b. 1982)
49. Hon. James Lascelles (b. 1953)
50. Rowan Lascelles (b. 1977)
51. Tewa Lascelles (b. 1985)
52. Sophie Lascelles (b. 1973)
53. Hon. Jeremy Lascelles (b. 1955)
54. Thomas Lascelles (b. 1982)
55. Ellen Lascelles (b. 1984)
56. Amy Lascelles (b. 1986)
57. Tallulah Lascelles (b. 2005)
58. Henry Lascelles (b. 1953)
59. Maximilian Lascelles (b. 1991)
60. James Carnegie, 3rd Duke of Fife (b. 1929)
61. David Carnegie, Earl of Southesk (b. 1961)
62. Lord Charles Duff Carnegie (b. 1989)
63. Hon. George William Carnegie (b. 1991)
64. Hon. Hugh Alexander Carnegie (b. 1993)
65. Lady Alexandra Etherington (b. 1959)
66. Amelia Mary Carnegie Etherington (b. 2001)
67. HM King Harald V of Norway (b. 1937)
68. HRH Crown Prince Haakon of Norway (b. 1973)
69. HH Prince Sverre Magnus of Norway (b. 2005)
70. HRH Princess Ingrid Alexandra of Norway (b. 2004)
71. Princess Martha Louise of Norway (b.. 1971)
72. Maud Angelica Behn (b. 2003)
73. Leah Isadora Behn (b. 2005)
74. Emma Talullah Behn (b. 2008)
Haakon Lorentzen (excluded by marrying a Roman Catholic)
75. Olav Lorentzen (b. 1985)
76. Christian Lorentzen (1988)
77. Sophia Lorentzen (b. 1994)
Ingeborg Lorentzen (excluded by marrying a Roman Catholic)
78. Victoria Ribeiro (b. 1988)
Ragnhild Lorentzen (excluded by marrying a Roman Catholic)
Alexandra Lorentzen (excluded by marrying a Roman Catholic)
79. HH Princess Astrid of Norway (b. 1932)
80. Alexander Ferner (b. 1965)
81. Stella Ferner (b. 1998)
82. Carl-Christian Ferner (b. 1972)
83. Cathrine Johansen (b. 1962)
84. Sebastian Johansen (b. 1990)
85. Madeleine Johansen (b. 1993)
86. Benedikte Ferner (b. 1963)
87. Elisabeth Ferner Beckman(b. 1969)
88. Benjamin Ferner Beckman (b. 1999)
Michael, King of Romania (excluded by marrying a Roman Catholic)
89 . Princess Margarita of Romania (b. 1949)
90. Princess Helen of Romania (b. 1950)
91. Nicholas Medforth-Mills (b. 1985)
92. Karina Medforth-Mills (b. 1989)
93. Princess Irina of Romania (b. 1953)
94. Michael Kreuger (b. 1985)
95 Princess Sophie of Romania (b. 1957)
96. Elisabeta-Maria Biarneix (b. 1999)
Princess Marie of Romania (excluded by marrying a Roman Catholic)
Crown Prince Alexander of Yugoslavia (excluded by marrying a Roman Catholic)
97. Prince Peter of Yugoslavia (b. 1980)
98. Prince Philip of Yugoslavia (b. 1982)
99. Prince Alexander of Yugoslavia (b. 1982)
100. Prince Nikolas of Yugoslavia (b. 1958)