No they didn't, monarchs in England started losing power quite some time ago, you could historically trace the beginning of that process to the magna carta.
The current monarchs of the UK and Northern Ireland were invited by parliament to take their current role in the House of Hanover (act of settlement), later through marriage renamed Saxe-coburg-gotha, and finally the House of Windsor.
They never really had the power to brutalise people in the way Saudi Monarchs can.
Not sure I agree with that (and my response was a humorous dig, not a historical analysis of Royal power) and until the Stuart's were replaced by the Hanoverians the royal family generally believed in the Divine Right of Kings.
As to brutality Henry VIII authorised the boiling alive of a poisoner and had three Protestants burnt at the stake for heresy and, just to be balanced, had three Jesuits hung drawn and quartered for treason on the same day.
Mary continued the theme by regularly burning Protestants and Elizabeth, to a lesser extent, applied the same tactic to the opposition by burning Catholics, as well as beheading her cousin, Mary Queen of Scots.
Charles II was a patron of the Royal Africa Company - you can probably guess what commodity they traded in.
Actually the Hanoverians repression of the Scots after Culloden was pretty brutal as well so there may be more similarity between historic British monarchy and the Saudis than you think.