The common law rules relating to tacking have caused difficulty in relation to overdrafts and revolving loan facilities because of the rule in Clayton's Case,[REF] which provided that in relation to any account, payments into the account are presumed to discharge the earliest debts first.
The subsequent mortgagee takes subject to the overdraft only at that time, that is to say, not subject to future advances, and the reduction of the overdraft correspondingly improves his security.