The word "dangerous" in the section has been the subject of some judicial examination and its meaning may be taken to be settled by authority. At the one extreme dangers are to be excluded from consideration which are only the result of the deliberate action of individuals or of action which could not be reasonably anticipated. At the other extreme, it is to be recognized that the purpose of the provision is to see that the workmen are protected, even though from consequences of their own lack of care, inadvertence, mistakes or even foolishness. Further, the kind of dangers to be considered includes dangers to persons who may come into the proximity to the machine, although not at work upon it, as well as to persons who operate the machine or whose work takes them to it. In Hindle v. Birtwhistle [5] , Wills J. said that machinery or parts of machinery is or are dangerous if, in the ordinary course of human affairs, danger may be reasonably anticipated from the use of them without protection, and added, that the contingency of carelessness on the part of the workman in charge of it and the frequency with which that contingency is likely to arise are matters that must be taken into consideration. He described the question as entirely a question of degree. In Walker v. Bletchley Flettons Ltd. [1] , du Parcq J. quoted the observation of Wills J. [2] and said if he were to venture to expand a little what his Lordship said he would say, and he thought he was saying nothing inconsistent with what that learned judge had said, that a part of machinery is dangerous if it is a possible cause of injury to anybody acting in a way in which a human being may be reasonably expected to act in circumstances which may be reasonably expected to occur. These authorities were applied to analogous language in s. 55 of the Coal Mines Act 1911 Imp. in Smithwick v. National Coal Board [3] . Tucker L.J. adopted from a textbook the statement that the behaviour of human beings that has to be regarded is such behaviour as is reasonably foreseeable, which is not necessarily confined to such behaviour as is reasonable behaviour, and went on to say: "An employer, of course, has to contemplate acts of carelessness, acts of negligence, and so on, but he has not to fence what would otherwise be a dangerous part of the machinery which is really inaccessible and to which no ordinary reasonable workman would be expected to go anywhere near or to come into contact with in any way" [4] . Denning L.J. said: "I think that the test for this purpose is substantially the same as the test whether machinery is "dangerous" within the Factories Act, 1937. It is "dangerous" if it is such that it may reasonably be foreseen to be a source of injury to people who may be in the vicinity, taking them with all the ordinary infirmities to which human nature is prone. The occupier must realize that not everybody is careful: many are hasty, careless or inadvertent; some are unreasonable, or even disobedient. It may be unlikely that they will act in such a way, but it is not only the likely but also the unlikely accident against which the occupier must guard. He must guard against all conduct which he can reasonably foresee. The limit of his responsibility is only reached when the machinery is safe for all except the incalculable individual against whom no reasonable foresight can provide - the individual who does not merely do what is unlikely, but also what is unforeseeable, or, at least, not to be foreseen by any ordinary man" [5] .