It may not have always been a smooth road and it certainly had its ups and downs - but the basic principles of a fair go were put together at Magna Carta, which began the process by clarifying rights of the 'ruling classes', then was extended by the introduction of The Common Law (which means simply that one law was the law of the land, and not one law for every separate jurisdiction), and gradually through the centuries the rights of all were steadily upgraded under English law and provided the basis for many legal advances, such as the abolition of slavery and even the Royal Navy attacking slavers not of their jurisdiction.
Of course - at every step those with the their hands on the controls, including many in the judiciary, have tried to slow down or even reverse this process for reasons of maintaining some myth of a status quo, lest the peasantry gain too much power and 'get above their station'* - something nowhere seen more clearly than in your Napoleonic figures in this nation, such as John Howard The Infamous Coward and Betrayer Of Worlds.
But the principle remains the same - it was the advances of the English Law that either gave directly further advances in rights and legalities, or inspired others, such as the United States, to build on that basic.
I think you could safely say that much of the rights enjoyed by the many are the result of the British Empire...
* Hush, but I tellz yez - there's be a terrible day of judgement some day soon......