Judgment :- 1. In execution of a decree declaring a right of way as an easement of necessity and allowing consequential reliefs, the decree-holders took steps to carve out the way provided in the decree by the issue of a commission. Judgment-debtors objected on the ground that subsequent to the decree the easement of necessity ceased to exist by the decree-holder acquiring another way by the purchase of an adjacent property and therefore the decree has become unexecutable. That contention was rejected by the execution court which held that it cannot go behind the decree. Judgment debtors have come up in revision challenging that order. 2. Whether there was acquisition of an adjacent property after the decree by the decree-holder providing another access to the dominant tenement of the decree-holder itself is a moot point on a question of fact. A decision on that aspect and a consequent finding that the decree has become unexecutable by cessation of the easement of necessity declared by the decree are conditions precedent to accepting the objection that the decree has become unexecutable. The question for consideration is whether the execution court can go to that extent. 3. Easement of necessity arises on the severance of tenements by transfer inter vivos, bequest or partition as envisaged in clauses (a), (c) and (e) of S.13 of Indian Easements Act, 1882. Transferor, transferee, testator, legatee or sharer, of a portion of an undivided estate in any of the above cases is entitled to such an easement provided it is necessary for enjoying the subject of transfer, bequest or partition and in the case of a testator for enjoyment of what remains with him. For that purpose no express provision in the document making a grant is necessary because the rationale or the legal basis of it is not any express grant but an implied grant as of necessity for enjoyment. Lands could be conveniently enjoyed in many cases only if the owner is able to have access to it and therefore the doctrine of implied grant is to meet the necessity of a particular case to avoid land lock. Law prescribes an easement by implied grant in such cases only to the extent of absolute necessity and not for convenient or reasonable enjoyment. The right is only in cases where without it the tenement cannot be used at all. Law prescribes an easement by implied grant in such cases only to the extent of absolute necessity and not for convenient or reasonable enjoyment. The right is only in cases where without it the tenement cannot be used at all. It is the outcome of the former jointness which was severed resulting in necessity of fresh access. When property is conveyed which is so situate relatively to that from which it has been severed that it cannot be enjoyed without a particular privilege in or over the land of the grantor, the grant of it is implied and passes over without any express words. The word 'necessary' will have to be construed in its ordinary sense. When there is another means by which there is access the question of such an easement will not arise at all because 'necessity' implies that it is not a rule of convenience. Mere common ownership and subsequent severance will not create an implied grant. 4. The English Law on this aspect is more or less akin to the Indian Law. As observed in 130 English Reports 233 the way of necessity is limited to the necessity which created it, and ceases, if at any subsequent period the party entitled to it can approach the place to which it led, by passing over his land. Easement of necessity must terminate when the necessity ceases. A way of necessity is extinguished when the necessity terminated by the dominant owner acquiring adjoining property through which he can pass and repass to the old dominant tenement without reference to the servient tenement. When once the right is thus extinguished it may be capable of revival hot not by a unilateral act on the part of the beneficiary. This position has been recognised by Indian decisions also as evidenced by the decision in Venkatapathiraju v. Subbaraju (AIR 1930 Madras 789). This principle has been given statutory recognition under S.41 of the Indian Easements Act which provides that an easement of necessity is extinguished when the necessity comes to an end. The right of way of necessity which arises by implication of law is a grant of a right of way until such time as the grantee may acquire the power from some other source of reaching the quasi-dominant tenement. 5. The right of way of necessity which arises by implication of law is a grant of a right of way until such time as the grantee may acquire the power from some other source of reaching the quasi-dominant tenement. 5. That takes us to the further question whether the execution court can or is bound to entertain such a plea whenever it is made. Execution court is bound by the decree and normally its duty and power is only to execute the decree and not go behind it. It cannot question the legality or correctness of the decree because it is concerned only with execution, discharge or satisfaction of the decree. But there is one well recognised exception to this rule. That is when the decree sought to be executed is found to be a nullity for lack of inherent jurisdiction of the court which passed it. That goes at the root of the jurisdiction of the court to pass it and involves no question of going behind the decree because in such a case the decree is void and non est and there is no question of it being enforceable. It can be challenged not only in execution but in collateral proceedings as well. Execution court can refuse to execute such a decree without incurring the reproach that it is going behind or beyond the decree. (See Sunder Dass v. Ram Prakash (1977) 2 SC 662) 6. Normally the execution court cannot take into account facts and events taking place after the decree has become final and conclusive between the parties unless there is legal sanction for that purpose. It is true that the execution court is having the jurisdiction to interpret the decree, but under that guise it cannot make a new decree. The duty of the execution court is only to give effect to the terms of the decree. Execution court has no right to vary the conditions of the decree, when a decree imposes obligations on both sides which are so conditioned on performance by the other, performance by the other will not be ordered unless the party seeking execution not only offers to perform his part but satisfies the execution court that he is in a position to do so when objection is raised. When obligations under the decree are reciprocal, and are interlinked so that they cannot be separated, as held in Jai Narain v. Kedar Nath (AIR 1956 SC 359) any attempt to enforce the decree unilaterally would be to defeat the decree and go behind it. 7. There are cases in which the execution court could take note of events subsequent to the passing of the decree which has become final and conclusive even though ordinarily a court should deal with the rights of parties as they stood at the institution of the suit. That is where the continued existence of these rights is an essential requisite for according the relief asked for and granted. But even in such cases whether execution should be allowed to proceed or disallowed or the aggrieved party directed to ventilate his claim in a separate suit are matters to be decided by the execution court in the facts and circumstances of each case as held in Ramabhadra v. Ramanna (AIR 1952 Madras 125). The execution court may be justified in refusing to execute the decree for restitution of conjugal rights when it was followed by a decree for divorce because as between divorced spouse it may be ridiculous and illegal to execute the earlier decree. In such cases no factual investigation on any subsequent event is necessary by the execution court to decide that the decree is not executable. 8. On the other hand there may be cases where the events that have transpired might be of such a nature that to ascertain the truth of what happened and their legal effect the execution court may have to bold a protracted enquiry to decide on disputed facts in order to conclude whether execution should be allowed or refused. In such cases it may be more appropriate that the parties settle the matter by a separate suit. In a case when a legislation intervened making the decree abortive, the execution court can very well refuse to execute the decree because it is only a question of looking into the legislation. So also there may be cases where a subsequent decree destroyed the rights of parties under the decree sought to be executed. In a case when a legislation intervened making the decree abortive, the execution court can very well refuse to execute the decree because it is only a question of looking into the legislation. So also there may be cases where a subsequent decree destroyed the rights of parties under the decree sought to be executed. Ramabhadra v. Ramanna (AIR 1952 Madras 125) is a case where a decree for possession obtained by a lessee under S.9 of the Specific Relief Act was resisted on the basis of an alleged subsequent quit notice which was claimed to have terminated the relationship making the decree not enforcible. The contention was repelled on the ground that is has to be decided in a separate suit since the validity of the notice is a matter for proof on facts. 9. S.47 of the Code of Civil Procedure bars a suit to enforce an executable judgment. But in order to entertain an application under S.47 involving execution, discharge or satisfaction of the decree, the decree must not only be subsisting but also be capable of being executed. The question whether a decree is capable or incapable of being executed is, therefore, preeminently one coming under S.47 and has to be entertained by the execution court. Incapability of execution may sometimes be inherent in the decree itself. A mere declaratory decree which does not direct anything further to be done may not be capable of execution. There may be cases when on account of a subsequent legislation or agreement of parties the decree has become unexecutable. Events that transpired subsequent to the decree may also sometimes affect excitability by the relief becoming not enforceable or the decree holder becoming not entitled to it. So also the execution court can refuse to execute the decree obtained ignoring the provisions of any statute. For example, when a landlord obtains decree for possession of a building coming within the purview of the Rent Control Legislation without recourse to the provisions of that legislation the execution court can refuse to execute the decree and say that an order from the Rent Control Court is necessary. A subsequent decree nullifying the effect of the previous decree is also a circumstance that the execution court can take into account in entertaining a contention that the decree has become unenforceable and thus unexecutable. A subsequent decree nullifying the effect of the previous decree is also a circumstance that the execution court can take into account in entertaining a contention that the decree has become unenforceable and thus unexecutable. But in the case of a decree which is apparently valid and executable between the parties, the execution court may not be justified in entertaining an objection regarding non¬executability of the decree based on facts or events subsequent to the decree requiring detailed investigation and decision. In such cases proper wisdom will only be to direct the aggrieved party to have his grievance redressed in a fresh suit. 10. In the present case the decree declaring the easement right of necessity and providing for execution was confirmed in appeal and second appeal. It was only when the decree-holder applied in execution to issue a commission to demarcate the pathway that the contention was raised that the decree is not executable because the necessity terminated by the decree-holder acquiring another adjacent property through which he has access. That is a matter on which investigation into the factual question and an independent decision on the question of fact and law is necessary before deciding either way. The execution court is not expected to take up that which has to be done on the trial side. If such objections are allowed it will be opening flood gates for unscrupulous judgment-debtors to defeat and delay execution of the decrees by raising mala fide contentions. The present suit was filed nearly 32 years ago in 1955. If on this contention which is a mixed question of fact and law on the basis of alleged events that transpired after the decree the decree-holder is denied the fruits of his litigation that will work out injustice and burden the execution court with a task that has to be taken up on the trial side. Therefore, I am of opinion that the contention cannot be raised in execution and the revision petitioners, if they are so advised, will have to seek their chance trial side in appropriate forum. The Civil Revision Petition is therefore dismissed without any order as to costs.