Agency law deals with the problems arising when A acts on behalf of B. A normally has a contract with B, but whether he has or not, he will be subject to fiduciary duties developed from the law of equity and trusts. A third party dealing with an agent will normally not know what powers the agent is entitled to exercise- what happens when the agent makes a contract with the third party which he has no authority to make?
Equity is a distinctive feature of common law systems. It operates in parallel to the rules of the common law, adjusting and supplementing them, providing practical and flexible remedies to numerous problems in almost all fields of law.
The trust itself was the first concept in equity. Evolved at the time of the Crusades it still provides vital solutions to problems of ownership- whether pension fund investments or or jointly owned homes. It has been described as ‘the greatest and most distinctive achievement performed by Englishmen in the field of jurisprudence.