Secret services got their start in Elizabethan (I) England and it does have something to do with British history and that history was the bloody civil war between the factions. Spying on citizens as a matter of state security came into being during her reign, as a natural product of a society divided against itself, sometimes even in the same (extended) family.
> European feudal societies .. government is expected to care for citizen
Feudal societies had no notion of “citizen”. Nor was the “government” ever tasked with ‘caring’ for the poor. That, as a matter of fact, was the domain of the church and in England the monasteries (that were destroyed during the above mentioned bloody civil war that raged for a long time). After the demise of the monastic system of caring for the poor, and after the lands of the church were confiscated and parceled out to the winning nobility, which gave rise to the British “manor”, for the first time the notion of poor houses became central. And that is when the post-feudal (new order) British Capitalist system gave rise to charities, poor houses, debtors prisons, etc.
The other historic “British” factor here is the propensity of the English for intrigue. They spy the heck on each other because they know themselves.