Complex sentence: The Succession to the Crown Act 2013 (c.20) is an Act of the Parliament of the United Kingdom which altered the laws of succession to the British throne in accordance with the 2011 Perth Agreement.
Split into simpler sentences: The Succession to the Crown Act 2013 (c.20) is an Act of the Parliament of the United Kingdom. It altered the laws of succession to the British throne in accordance with the 2011 Perth Agreement.