How much power did King George iv have?

Answer 1

Not as much as he would have had you believe. In 19th century, Parliament were making the laws and effectively governing the country. The King, of course had regular audiences with the incumbent Prime Minister, and the King's opinions would have been made known.

Although the sovereign was largely removed from the political arena, his wishes were always viewed as commands, and he was still the figurehead on ceremonial occasions. He was not unhappy with this, as he was overfond of huge banquets (at the State's expense) and gambling (horses mostly) - and assorted mistresses.