Broadly, this principle enables the courts to decide whether someone has acquired a right to a property because of promises made to them in the past, which they have relied upon to their detriment, in the absence of a written agreement.
Three criteria must be met for a successful claim:
Michael has two adult children, Jane and Mary. Michael becomes seriously ill and promises Jane that if she moves in with him and becomes his fulltime carer, she will inherit the family home on his death. Jane quits her job and moves in with her father to care for him.
When Michael passes away years later, his Will leaves the family home to Jane's sister, Mary. Jane may be successful in bringing a proprietary estoppel claim, against her late father's estate.
In a family relationship based on trust, it is often very hard for an adult child to demand their parent to commit a promise into a legally binding written agreement. As a result, proprietary estoppel is a notoriously complex area of law and outcomes can be difficult to predict.
If you find yourself in this situation, our advice is that you should try to achieve a legally drafted agreement setting out the arrangement, however difficult, rather than have to rely on bringing hugely expensive court proceedings later down the line, with an uncertain outcome.