22.1 While some maritime liens and statutory liens are founded on contract they are consequences imposed by the law on the contract. The parties have no freedom to create either type of lien by a contract other than that which by law exists in the lien.1 On the other hand under English law possessory and equitable liens may be created by contract in respect of any type of transaction. Subject to estoppel or statutory provision2 a lien may not be created by contract in respect of any asset in which a contracting party has no interest to support the lien.