(A) THE FUNCTION OF THE LACHES DEFENCE
Laches is an equitable doctrine which defeats the claimant’s equitable claim where there has been an unreasonable delay in the claimant suing the defendant. The defence is potentially applicable whenever cases where the claimant seeks an equitable remedy, such as an account of profits, rescission for equitable grounds, and equitable proprietary remedies. The rationale of the defence is that the claim should be defeated where there is such a delay in commencing proceedings that it would be unjust to the defendant to allow a claimant to enforce his or her rights. Laches can apply only where there is no statutory limitation period available in respect of the claim.  The doctrine will, however, be available where the Limitation Act states that there is no prescribed period of limitation under the Act, such as where the trustee is sued for a fraudulent breach of trust or where the claimant seeks to recover trust property.
The function of the defence was identified by the Privy Council in Lindsay Petroleum Co v Hurd in the following terms:
the doctrine of laches in courts of equity is not an arbitrary or technical doctrine. Where it would be practically unjust to give a remedy, either because the party has, by his conduct, done that which might fairly be regarded as equivalent to a waiver of it, or where by his conduct and neglect he has . . . put the other party in a situation in which it would not be reasonable to place him if the remedy were afterwards to be asserted . . . lapse of time and delay are most material. But in every case, if an argument against relief, which otherwise would be just, is founded upon mere delay... the validity of that defence must be tried upon principles substantially equitable. Two circumstances, always important in such cases, are, the length of the delay and the nature of the acts done during the interval, which might affect either party and cause a balance of justice or injustice in taking the one course or the other, so far as relates to the remedy.
-  64 The doctrine oflaches is implicitly preserved by the Limitation Act 1980, s 36(2). See Re Loftus (deceased)
-   EWCA Civ 1124,  1 WLR 591,  (Chadwick LJ).
-  65 Erlanger v New Sombrero Phosphate Co (1878) 3 App Cas 1218, 1279 (Lord Blackburn).
-  66 Allcard v Skinner (1887) 36 Ch D 145.
-  Re Loftus (deceased)  EWCA Civ 1124,  1 WLR 591,  (Chadwick LJ).
-  Ibid,  (Chadwick LJ). 69 (18 74) LR 5 PC 221, 239-40.
-  70 Re Loftus (deceased)  EWCA Civ 1124,  1 WLR 591,  (Chadwick LJ). See also Lindsay