Waller-Edwards v One Savings Bank Plc 1 has tied up a loose end regarding whether a lender is “put on inquiry” for a non-commercial lending of a “hybrid” nature—that is, where the borrowers seek a loan partly for their joint purposes (the joint loan element) and partly for the benefit of one borrower only (the surety element). The issue for the Supreme Court was what legal test was appropriate to determine whether a lender is put on inquiry as to any undue influence between borrowers in such loans. It was held that any non-commercial hybrid transaction which involves a non-trivial surety element is to be treated as a surety transaction such that a lender is put on inquiry. The Supreme Court’s decision should be generally welcomed, but it breathes new life into old criticisms levelled at this judge-made contractual institution.