In England in 1700, would defending property with lethal force be illegal at all?

Question

My limited understanding is that without an extensive police force and good communications, much of what modern people would leave to police was handled directly. If so, were any questions asked of a land owner who killed a poacher or robber or thief? Or was it not only in practice but by law allowed for someone to kill any trespasser?

EDIT: Let us say, England in 1700. Almost modern but no police force yet in London and we read in Newton and the Counterfeiter that traveling twixt Cambridge and London was dangerous, just as it was in Chaucer's time: travelers sought protection by waiting at an inn until enough were in the their party to help fight off brigands.

EDIT: Let's ask if killing a trespasser was actually illegal or if not, whether in practice the killing was punished at all. Of course, robbers and other invaders are also at least trespassing.

Answer 1

The Killing a Thief Act of 1532 (24 Hen. 8, c. 5) legalised using lethal force against highway robbers or home burglars as justifiable homicide.

Eventually the British Parliament closed this gap in the common law, enacting a statute in 1532 that essentially licensed the killing of robbers and other assailants on the pubic highway. This statutory defense came to be called justifiable - as opposed to excusable - homicide.

_{Fletcher, George P., and Jens David Ohlin. Defending Humanity: When Force is Justified and Why. Oxford University Press, 2008.}

English law made a distinction between justifiable homicide and excusable homicide. Because the Crown reserves for itself all rights to use force, only killings on behalf of the king were justified. Homicides of other reasons were merely excusable at best, and the perpetrator had to apply for a pardon from inside a cell. Hence the adage, killing in self-defence "deserved but needed a pardon". Royal clemency was effectively a compromise between the common law, which forbade killing, and the natural law, from which a right to self-defence originated.

By 1700, the guiding principle had become whether the other party was committing a felony. In other words, robbers and home invading thieves could be killed in self-defence on the king's behalf, because they were felons. In the absence of a police force, it was practically a public service to rid the land of these criminals. The same would be true of would-be murderers or arsonists, of course.

Trespassing, however, was not a felony, and did not entitle the victim to use lethal force. In fact, Sir Edward Hyde East's 1803 treatise Pleas to the Crown specifically says:

[I]f one come to beat another, or to take his goods, merely as a trespasser; though the owner may justify the beating of him so far as to make him desist; yet if he kills him, it is manslaughter. But if the other had come to rob him, or take his goods as a felon, and were killed in the attempt, it would be justifiable self-defence.

_{East, Edward Hyde. A Treatise of the Pleas of the Crown. London: J. Butterworth and J. Cooke, 1803.}

Note while this was written a century after your specified time, in making these assessments East was still citing and explaining the 1532 law.