Although a will is revocable until death or loss of testamentary capacity, equity enforces a contract not to revoke a will, or to leave property by will, not by restraining or nullifying an inconsistent will, but by fastening a trust on the estate to give effect to the contract: Birmingham v Renfrew [1937] HCA 52, 57 CLR 661, 683. A contract to leave an identified property by will is specifically enforceable against volunteers who claim under a disposition by the promisor in his lifetime: Synge v Synge [1894] 1 QB 466 CA, 470-1, but is subject to the claims of creditors if the estate is insolvent: Schaefer v Schuhmann [1972] AC 572, 586 … Handely AJA in Delaforce v Simpson-Cook [2010] NSWCA 84 at 31.