English Constitution in 1700
The unchanged consitution
In comparison to others the English constitution has changed the least since 1700. This shows clearly how far ahead the United Kingdom was at the time. Even though all people have the right to vote nowadays, and the queen does not have much to decide anymore, the basics of the English constitution are still the same now as they were in 1700.
Cornerstones of the English consitution
Up till the reign of Charles I the English constitution still relied on medieval tradition. A written document like the Magna Charta describes only some topics of this tradition. In essence the constitution provided that the powers of the king were limited to those he held by tradition. These were the income from customs and the aid he was entitled to in certain circumstances (e.g. a war). Charles I tried to break this tradition by lifting new taxes without the consent of parliament. This conflict led to the Petition of Right coming into force in 1628, which again affirmed the Common's authority over taxation.
The conflict between crown and parliament did not end with the petition of right. In 1640 the Law to dissolve the Star Chamber, also known as '1640 Habeas Corpus act', was passed and effectively took judicial power out of the King's hands. The moves by Charles I ultimately led to the English Civil War, the Commonwealth and the Restoration. Under king Charles II the Habeas Corpus act came into force in 1679. His successor James II made another attempt to supersede parliament and in reaction the population dismissed him with the help of William III.
King William III thoroughly understood and probably even intended that his powers would be limited. The declaration of rights and the Bill of Rights were mainly presented as once again listing the constitutional relations in the kingdom. They were followed by the Act of Settlement. All this was presented as a restoration of the rights of parliament and free Englishmen, but in fact established parliamentary sovereignty.
Lawmaking, executive and judicial powers
The essence of the English constitution was that lawmaking, executive and judicial powers were rather separated. Roughly put; Laws were made by parliament (House of Commons and House of Lords). Laws were executed by the government (king + secretaries). In individual cases the proper execution of the law was checked by the judiciary. In this theory the budget law it the biggest law of them all. E.g. parliament allowed a budget for war, the government spent the money by paying soldiers etc.