Section 3 of the Act relates exclusively to light, but it must be read in connection with Section 4, so that while Section 3 enacts that, in order to acquire an "absolute and indefeasible" right to light, access, use, and actual enjoyment "for the full period of twenty years " are necessary ; Section 4 provides in effect that the "full period of twenty years shall be deemed and taken to be the period next before some suit or action wherein the claim . . . shall have been or shall be brought into question."

It is not just any period of twenty years of uninterrupted use and enjoyment which will satisfy the requirements of the Act, but the particular period just before such suit or action is started in which the claim to light is brought in question. It is not essential in all cases that the time should be counted backwards from the particular suit then before the Court, if there has been any prior suit or action in which the matter was brought in question, though naturally, in the great majority of ordinary cases, the twenty years immediately preceding the institution of the particular suit or action then pending will be the time during which uninterrupted enjoyment must be proved.

The important point to notice concerning access, use, and enjoyment of light is that no amount of time, however great, will of itself confer any complete right under the Act. The right is at best what has been called an inchoate right until some suit or action has been instituted, when it may become absolute and indefeasible if the uninterrupted use and enjoyment for the immediately preceding twenty years are proved.

It follows therefore from what has been just stated that when a neighbour puts up structures upon his own land which obstruct lights to his neighbour's windows, he is acting prima facie within his rights, so far at least as the Prescription Act is concerned, unless there has already been a law suit concerning those lights ; and if he maintains the obstruction for a whole year, the owner of the house with windows cannot afterwards compel the removal of the obstruction or maintain a prescriptive claim for light to those windows.

If windows have not been in existence for a full twenty years before they are obstructed, he cannot sue for the removal of obstruction, because he has not even an inchoate right to an easement, and only at best a bare chance of acquiring such a right. If, however, he has enjoyed the uninterrupted access and use of light for a full twenty years, he has acquired such right, and any time within a year of the obstruction he may institute an action and allege and prove his inchoate prescriptive right, which will then become absolute and indefeasible, after which he can obtain all appropriate legal remedies to protect his absolute and indefeasible right, - as, for example, by recovery of damages, or by ordinary or mandatory injunction get rid of the threatened or actual nuisance affecting his rights.

The mere opening of windows in a building and keeping them in a state and condition such that it can be held that the owner has had access and use and enjoyment of light for a full period of twenty years would ordinarily suffice for the development of an inchoate right, such as could be made absolute at any time thereafter, provided, of course, that they were not abandoned or obstructed in such fashion as to destroy the right.

It is possible, however, to provide against an accrual of an easement of light by access, use, enjoyment, and efflux of time followed by suit, by providing specially for the enjoyment "by some consent or agreement expressly made or given for that purpose by deed or writing."

The meaning of the expression "actual enjoyment" in Section 3 has been discussed in several reported cases, and it is apparently settled that "actual enjoyment" does not necessitate or imply continual use. Intermittent use is sufficient. Windows may be temporarily closed by shutters, and only occasionally opened for special purposes at more or less distant intervals of time, or they may be partially covered up by shelves, without the owner losing the benefit of "actual enjoyment" as provided in the Act; but when windows had been boarded up internally for several year it was held that there had been no actual enjoyment during that time. Enjoyment is a question of fact to be decided in each case according to the particular circumstances.

In one case it was questioned whether there could have been actual enjoyment within the meaning of the statute when a house had been built and windows put in and roof put on, but the inside left in such condition that the house was uninhabitable, or in fact uninhabited, during the whole prescription period of twenty years before suit.

It was held that under such circumstances the statute is satisfied, and that no personal occupation is necessary to constitute "actual enjoyment" within the meaning of the Act. Concerning the commencement of the prescription period of twenty years, questions may sometimes arise. In the case of new windows in an old building, time may ordinarily begin to run in favour of that window from the time it is first put in, and in the case of new building from the time the shell of the building is covered in by a roof, assuming, of course, that the window spaces are there at the time.

The meaning of the term "interruption" in Section 3 of the Act is explained in Section 4. "No act or other matter shall be deemed to be an interruption within the meaning of the statute unless the same shall have been or shall be submitted to, or acquiesced in for one year after the party interrupted shall have had or shall have notice thereof, and of the person making or authorising the same to be made."

Interruption means some obstructive act by somebody other than the person whose lights are obstructed, and should be of such character as to stop enjoyment. The words "without interruption" in the Act do not mean "without intermission." Before the passing of the Prescription Act there was an established custom in the cities of London and York under which owners of houses or of ancient foundations in either city might build to any height upon the old foundations, or raise existing houses to any extent, without regard to the way in which light to neighbouring houses would be interfered with by the new building.

The Prescription Act overrides that custom, and in effect destroys it, because it gives an absolute and indefeasible right to unobstructed light under conditions prescribed by the Act - "any local usage or custom notwithstanding."

It is important also to note that, as regards light, no right to an easement can be acquired against the Crown under the Act. Other easements referred to in other sections of the Act can be acquired over Crown Lands as over lands of private owners, but all reference to the Crown is omitted from Section 3 of the Act, and as a consequence the Act does not apply to Crown Lands.

It follows, therefore, that not only can no prescription right to light under the Act be acquired against the Crown, but also no matter how long windows overlooking Crown Land may have been used and enjoyed, a purchaser from the Crown can build so as to obstruct light to those windows at any time within twenty years from the date of his purchase.

Of course, the Crown may make grants of easements of light by covenanting not to obstruct, or may enter into agreements relating to building on its own or neighbouring estates, but in the absence of any special deed or agreement by which the natural rights of the Crown may be restricted or an casement created, the general presumption is that Crown Lands are not servient to neighbouring tenements for light.

Also it may be noted that Section 3 of the Act does not require that there should be any claim of right while the prescriptive period is running. While, therefore, such easements as rights of way and water referred to in the second section of the Act must be enjoyed during the prescriptive period as of right (and not by permission or licence or in return for rent or fees paid for the enjoyment), in order to obtain the benefit of the Act to establish an easement, it is sufficient in the case of light if it is enjoyed during the period of twenty years, even though the enjoyment appears to be permissive, or if regular payments are made during the prescriptive period in consideration of the neighbour whose land is overlooked not objecting or interfering with the flow of light to the windows.

It is, however, necessary that the light should have been enjoyed after passing over the land of some owner other than the person enjoying the use of the light. An owner cannot acquire an easement over his own land. Rights which might amount to an easement over the land of another would only be part of the natural proprietory rights of the owner of the house and land. He could, if he liked, at any time so build on his own land as to obstruct any light going to any windows in his own house, or he could leave them unobstructed, but no amount of time would confer any privilege or inchoate right under the Prescription Act so long as the land and house were owned by the same person.

The intention of the Act is to define the law as regards the acquisition of prescriptive rights as between neighbours who may have conflicting interests, and to remove causes of dispute and injustice.