a representation can be inferred from silence where there is a duty to speak or from negligence where a duty of care arises. Under English law, estoppel by representation of fact is not a cause of action, though it may be a defence or acts in support of a cause of action. There is some debate whether under English law courts will take into account unconscionability under estoppel by representation of fact, although Australian courts clearly do. Lord Justice Lewison, in his judgment as to the circumstances obtaining at the time of the withdrawal of employment tribunal (ET) proceedings did not draw the conclusion that the appellant, Dr Srivatsa, intended to concede the merits of his claim when withdrawing his ET action. In allowing the appeal of Dr Srivatsa against a prior judgement of a cause of action or issue estoppel, and in respectful disagreement with the judge of first instance, he said that the effect of that judge's decision was that, in the words of Mummery LJ in the case of Sajid v Sussex Muslim Society: Equitable estoppel As noted above, under English law, promissory and proprietary estoppel are both species of equitable estoppel. Proprietary estoppel Proprietary estoppel arises when A purports to give but fails to effectively convey, or promises to give property or an interest in property, to B, while being generally aware (Crabb v Arun District Council) that B will expend money or otherwise act to his detriment in reliance of the supposed or promised gift, so much so that it would be "unconscionable" not to enforce the expectation (Taylor Fashions v Liverpool Victoria Trustees). For example, in Dillwyn v Llewelyn in Chancery a father promised a property to his son, who took possession, expended a large sum of money on the house and otherwise improved the property. The father never actually gifted the property to the son. After his death the son, claiming to be the equitable owner, obtained a court judgment forcing the trustees to convey the land to him. Similarly in Inwards v Baker, a father encouraged his son to build a house on his own land, promising to leave that land to the son in his will. Subsequently, the son built a house and lived there for some 30 years. No transfer of land was made in the father's will when he died. It was held that despite this the personal representatives