I would like to start by defining equity according to the Webster’s Dictionary as ‘a body of legal doctrines and rules developed to enlarge, supplement, or override a narrow rigid system of law’ (Marriam-Webster.com).
Also maxims is defined also by Webster’s Dictionary as ‘a general truth, fundamental principle, or rule of conduct’ (Marriam-Webster.com).
Therefore the maxims of equity may fairly be described as a set of general principles which are said to govern the way in which equity operates. They tend to illustrate the qualities of equity, in contrast to the common law, as more flexible, responsive to the needs of the individual and more inclined to take account of the parties’ conduct and worthiness.
In conducting this research, it cannot be said that there is a definitive list of the maxims: different sources give different examples and some works prefer to avoid the term altogether in favour of a broader discussion of the character of equity. Above all, the maxims are applied only when the court feels it appropriate: none of the maxims is in the nature of a binding rule and for each maxim it is possible to find as many instances of its not having been applied as instances where it has been.
I will give such instance, such as the role of the maxims was discussed in the case of Tinsley v Milligan [1993] 3 All ER 65, (which I will not go in detail). In the Court of Appeal a flexible approach was taken to the application of the maxim, ‘he who comes to equity must come with clean hands’, but in the House of Lords, this was rejected. Such a flexible approach, depending upon such an ‘imponderable factor’ as public conscience, would lead to great uncertainty (Halliwel, 2004). It is submitted that this cannot be taken as evidence that every maxim is binding in every situation which would appear to lie within its wording. The true answer may lie in the fact that the maxims are very broadly worded and cannot, as is stated above, be treated without more as binding rules. Rather they are the principles underlying various specific rules, instances of which are given below in the context of each maxim Halliwel (2004) stated.
The following is a list of maxims, together with some of the instances of their application. It is not intended to be exhaustive. It will also become apparent that there is much overlap and in some cases contradiction between the maxims.
 Equity Follows the law

This is an attempt to indicate the relationship between common law and equity, which is a complex one. The traditional role of equity, as stated in ‘Doctor and Student’ 1523 by Christopher St German was ‘to temper and mitigate the rigour of the law’, which implies that equity would intervene and overrule the common law if justice required it. It was stressed, even at that time, however, that it did not attempt to overrule common law judgments, but rather to act in personam on the parties to prevent injustice (as explained below, it is also a maxim of equity that it acts in personam). This maxim indicates that, where possible, equity will ensure that its own rules are in line with the common law ones. Examples of equity overcoming the effect of the common law are frequent enough, but it should be noted that in most cases the principle is that equity supplements but does not contradict the common law. Thus, in the case of the trust, the interests of the beneficiary are recognised, but so too, of course, is the status of the trustee as legal owner. The trust exists, as it were, behind the legal ownership (Halliwel, 2004).
Equally, the courts will in appropriate cases allow the common law effects to stand. For instance, in the case of Re Diplock [1948] 2 All ER 318 it was argued that, where money had been distributed to charities under the provision of a will which subsequently turned out to be invalid, the charities should be allowed to retain it. The Court of Appeal stated:
It is in our opinion impossible to contend that a disposition which according to the general law of the land is held to be entirely invalid can yet confer upon those who, ex hypothesis, have improperly participated under the disposition, some moral or equitable right to retain what they have received against those whom the law declares to be properly entitled (Halliwel, 2004).

 Where the equities are equal, the law prevails. Where the equities are equal, the first in time prevails

These two maxims are concerned with priorities, that are to say which of various interests prevails in the event of a conflict. The general rule, as one might expect, is that interests take effect in order of their creation, but, as regards equitable interests, these may be defeated if a bona fide purchaser acquires a subsequent legal estate without notice of the equitable one. This in turn raises the issue of notice, and to that extent the maxims have been affected by legislation on the question of what constitutes notice. For the purchaser of the legal estate to gain priority, however, it will be necessary for him to show that he is bona fide. If there is fraud then the equities (of the legal owner and the equitable one) will not be equal and the equitable one will prevail. In Pilcher v Rawlins (1872) LR 7 Ch App 250, James LJ explained the position of the bona fide purchaser of a legal estate thus: (Halliwel, 2004). such a purchaser’s [i.e. the purchaser of a legal estate’s] plea of a purchase for valuable consideration without notice is an absolute, unqualified, unanswerable defence, and an unanswerable plea to the jurisdiction of this Court [the Court of Appeal in Chancery]. Such a purchaser, when he has once put in such a plea, may be interrogated and tested to any extent as to the valuable consideration which he has given in order to show bona fides or mala fides of his purchase, and also the presence or the absence of notice; but when once he has gone through that ordeal, and has satisfied the terms of the plea of purchase for valuable consideration without notice, then . . . this Court has no jurisdiction whatever to do anything more than to let him depart in possession of that legal estate (Halliwel, 2004).
Again, if there is a conflict between a number of equitable interests, they will have priority in order of their creation, again subject to the ‘equities being equal’ (i.e. both parties not being at fault or guilty of fraud etc.) (Halliwel, 2004).
The sort of conduct by which a person might lose his priority, i.e. making the equities unequal, was characterised by the Privy Council in Abigail v Lapin [1934] AC 491 at 502 thus:
In the case of a contest between two equitable claimants the first in time, all other things being equal, is entitled to priority. But all other things must be equal, and the claimant who is first in time may lose his priority by any act or omission which has, or might have had, the effect of inducing a claimant later in time to act to his prejudice. (Halliwel, 2004). Ranking after equitable interests in the matter of priorities are mere equities, so that the bona fide purchaser of an equitable estate without notice of the equity will take free of it. Mere equities are difficult to define and some writers have said that they cannot bind subsequent purchasers in any event. It is submitted that there are certain defined equities which do bind, subject to the above rule regarding the bona fide purchaser. Such defined equities are proprietary interests, including, for example, the right to have a conveyance set aside for fraud, the right to have a contract rectified and a right arising out of estoppels. (Halliwel, 2004).
It is clear that the question of notice will be crucial in determining priorities, especially where both legal and equitable interests are in conflict. The general principle is that a purchaser is taken to have notice unless he can show he took all reasonable care and made inquiries and did not thereby acquire notice, whether actual, constructive or imputed. Actual knowledge means that he was actually aware of the interest, constructive knowledge that he would have acquired it had he taken all reasonable steps, and imputed knowledge is that which was possessed or should have been possessed by his agent acting on his behalf in the transaction. The detailed rules as to what is considered reasonable inquiry need not be examined here, but it should be remembered that in relation to real property the position is substantially affected by land charges legislation.
Under this legislation many charges on land, both legal and equitable, will be void against a purchaser for value unless registered and registration is deemed to be actual notice to all persons of the charge registered. Also important is the principle of ‘overreaching’ which has the effect of enabling a purchaser of land held on trust to take free of the beneficial interests even if he has notice of them. This occurs because the trust, and therefore the beneficial interests, attach to the purchase moneys rather than to the land in the case of land held on trust of land under the provision of the Trusts of Land and Appointment of Trustees Act 1996. (Halliwel, 2004).
 Equity looks to the substance rather than the form
Courts of Equity make a distinction in all cases between that which is matter of substance and that which is matter of form; and if it finds that by insisting on the form, the substance will be defeated, it holds it inequitable to allow a person to insist on such form, and thereby defeat the substance. Lord Romilly MR thus expressed this maxim in Parkin v Thorold (1852) 16 Beav 59. It should not be thought that this implies that formalities are never required, however. Equity will not enforce or recognise equitable interests where, for example, formalities are required by statute, as explained in Chapter 4 at page 102. Once again, this maxim is in the nature of a general principle only, which implies that equity is generally less concerned with precise forms than the common law. It is not necessary, for example, for the word ‘trust’ to be used before a trust can be created: the court looks not at the words of the settler, but rather the result he was attempting to achieve (Halliwel, 2004).
 Equity will not permit a statute to be used as an instrument of fraud

This principle, which is further discussed in Chapter 4 at page 111, may be taken as a more specific example of the previous maxim regarding formality. It should be stressed that equity will not ignore statutory requirements normally, but only, as the maxim implies, where it would be unconscionable to allow a party to rely on a statutory requirement to another’s detriment. This problem has commonly arisen in situations where contracts are only enforceable if in writing, as required by the Law of Property Act 1925 s 53(1) (b). (Halliwel, 2004).

Bannister v Bannister [1948] 2 All ER 133

In this case, A conveyed a house to B and B orally agreed to allow A to live in it rent free as long as she wished. This agreement was unenforceable as it was not in writing and B attempted to evict A. The Court of Appeal held that the agreement was enforceable, notwithstanding the requirement of writing and accordingly A was tenant for life.
(Halliwel, 2004).
This case is not without difficulty, because by holding A to be tenant for life the court gave her much wider powers, including the power to sell the land, than can have been intended. A further problem, that of the nature of the trust that equity imposes to prevent fraud, is discussed in the context of the similar case of Rochefoucauld v Boustead (1897). One of the theoretical justifications for secret trusts is that not to enforce them would allow a statute, in this case the Wills Act 1837, to be used as an instrument of fraud. (Halliwel, 2004).

 Equity imputes an intention to fulfill an obligation
This is the basis of the equitable doctrines of performance and satisfaction, and simply means that where a person has undertaken an obligation his later conduct will, if possible, be interpreted as fulfillment of that obligation (Halliwel, 2004).
 Equity will not suffer a wrong to be without a remedy
This maxim indicates that equity will not allow the technical defects of the common law to prevent worthy plaintiffs from obtaining redress. It could be seen, therefore, as the opposite of the maxim that equity follows the law. There are numerous examples of the development of equitable doctrines and remedies intended to override the unjust result arising from the enforcement of legal rights. Perhaps the most obvious is the trust itself: the enforcement of the rights of the legal owner as against the person for whose benefits t he had agreed to hold the property would clearly lead to injustice and so equity recognised the rights of that beneficial owner. Other examples include the use of specific performance to enforce contracts not enforceable at law and the use of injunctions to restrain threatened wrongs or to protect the plaintiff’s interests pending trial. (Halliwel, 2004).
 He who seeks equity must do equity

Though the previous maxim indicates equity’s willingness to intervene where the common law will not, it should not be thought that equity will automatically intervene whenever a certain situation arises. In general, one can say that wherever certain facts are found and a common law right or interest has been established, common law remedies will be available whether that produces a fair result or not. By contrast, equitable remedies are discretionary and the court will not grant them if it feels that the plaintiff is unworthy, notwithstanding that prima facie he has established an equitable right or interest. The maxim that he who seeks equity must do equity, together with the next two maxims, concerning ‘clean hands’ and delay, are aspects of this discretionary quality.
It should not be supposed that the discretion is entirely unfettered. As Lord Romilly MR explained in Haywood v Cope (1858) 25 Beav 140: (Halliwel, 2004).
The discretion of the Court must be exercised according to fixed and settled rules; you cannot exercise a discretion by merely considering what, as between the parties, would be fair to be done; what one person may consider fair, another person may consider very unfair; you must have some settled rule and principle upon which to determine how that discretion is to be exercised. (Halliwel, 2004).
So the person who seeks an equitable remedy must be prepared to act equitably, and the court may oblige him to do so. In the fi eld of contract, the court will not grant an injunction to prevent breach for the benefi t of a party who is not prepared to perform his side of the bargain (see Chappell v Times Newspapers [1975] 2 All ER 233). Where a contract is rescinded the party seeking rescission must be prepared to return all benefits received under it. A creditor may not be able to recover the full amount of a debt if the debtor can set off money owed to him by the creditor. The maxim is also behind the principle of mutuality of remedies (if specific performance is available to one party then it will be available to the other, even though damages would be adequate for that party) and the doctrine of election ( Halliwel, 2004).
This maxim refers to the plaintiff’s future conduct, whereas the next refers to his past
Behavior (Halliwel, 2004).
 He who comes to equity must come with clean hands

The rather picturesque language of this maxim means that a party seeking an equitable remedy must not himself be guilty of unconscionable conduct. The court may therefore consider the past conduct of the claimant. Most cases concern illegal or fraudulent behaviour on the part of the claimant, and it is not clear to what extent the maxim is applicable outside such behaviour. Certainly, in the context of the granting of injunctions, which, like all equitable remedies, are discretionary, the principle has been broadly stated; for example, Wood J stated in Cross v Cross (1983) 4 FLR 235: (Halliwel, 2004).
He who comes to equity must come with a clean hand and any conduct of the plaintiff which would make a grant of specific performance inequitable can prove a bar.
It appears, however, that the ‘uncleanness’ must relate directly to the matter in hand, otherwise anyone might be denied a remedy simply because he was of bad character.
Dering v Earl of Winchelsea (1787) 1 Cox 318 (Halliwel, 2004).
This is illustrated in the case of Dering v Earl of Winchelsea, where Sir Edward Dering, the Earl and another had acted as surety for Dering’s brother, Thomas, for the due performance by Thomas of the office of Collector of Customs. Thomas defaulted and the Crown obtained judgment from Sir Edward for the amount lost. Sir Edward then sought to obtain a contribution from the other sureties. The Earl claimed that Sir Edward could not claim the share because of his own misconduct. Eyre LCB (having itemised some of Sir Edward’s misconduct, including encouraging his brother to gamble, knowing his brother was using government money for this) did not accept that argument and stated that: (Halliwel, 2004).
. . . such a representation of Sir Edward’s conduct certainly places him in a bad point of view; and perhaps it is not a very decorous proceeding in Sir Edward to come into this Court under these circumstances: . . . A man must come into a Court of Equity with clean hands; but when this is said, it does not mean a general depravity: it must have an immediate and necessary relation to the equity sued for, it must be a depravity in a legal as well as a moral sense.
He concluded that though Sir Edward might morally be the author of his own loss he could not be said to be so legally, so his conduct did not prevent him from recovering the contribution. A similar point was made more recently in Argyll v Argyll [1965] 1 All ER 611: the Duchess’s immoral attitude towards her marriage did not prevent her obtaining an injunction to stop the Duke publishing an account of it. (Halliwel, 2004).
The application of this maxim to situations where a claimant seeks the recognition of an equitable proprietary right was considered in the case of Tinsley v Milligan, referred to in the introduction to this chapter. (Halliwel, 2004).

References
Halliwel, M. (2004) The Maxims of Equity. Retrieved from http://catalogue.pearsoned.co.uk/assets/hip/gb/uploads/M02_EDWA3458_10_SE_C02.pdf
Marriam Webster Dictionary (2011) Marriam-Webster Incorporation. Retrieved from http://www.merriam-webster.com/dictionary/equity