What is the test for retaining a deposit of 10% of the purchase price?

What must not be lost sight of here is that this is a case involving what is sometimes termed "earnest money", namely money paid as a deposit to ensure that the land sale transaction is adhered to by the purchaser. In the case of Collins v. Stimson (1882-83) 11 Q.B.D. 142, a bankrupt had entered into a contract to buy land and paid a deposit of 10% of the purchase price. When the purchaser failed to complete, the trustee in bankruptcy sought to recover the deposit. Baron Pollock, with whom Lopes J. agreed, held the deposit irrecoverable. At p. 143, he said "According to the law of vendor and purchaser the inference is that such a deposit is paid as a guarantee for the performance of the contract, and where the contract goes off by default of the purchaser, the vendor is entitled to retain the deposit." That is in effect the result argued for by the respondent here.