We start with a remote ancestor of today’s comprehensive health and safety regulation.
Wales v Thomas (1885) 16 QBD 340 concerned criminal proceedings brought in relation to the presence of inflammable gas at the Ynishir coal mine.
s 51 of the Coal Mines Regulation Act 1872 provided that general rules were to be observed so far as reasonably practicable.
Day J said
“I have next to consider whether an offence has been committed under s. 51, looking at the words “so far as is reasonably practicable” by which it is introduced. Some of the provisions in this section are affirmative, and to these I understand the limitation to apply, and no penalty is to be incurred through not carrying out those enactments where such a course is not reasonably practicable. Many of the provisions are negative, and generally speaking they must be practicable, because it is always possible to do nothing. It has been urged that if the thing which the legislature says shall not be done would yield profit to the colliery, then it may be done, and that seems to be the view taken by the magistrate. We have nothing to do with what is practicable for the carrying on the colliery as a profitable business concern, that is for the legislature. “
This early case shows an employer trying to argue that profitability should trump the requires of the health and safety provisions imposed by parliament. The argument did not succeed. Note however this this was a case of criminal and not civil liability.
See the later case of Edwards v National Coal Board  1 KB 704 for the view that profitability was indeed to something to be taken into account.