According to section 5(1) of the Compulsory Purchase Act 1965 (CPA 1965), a notice to treat must be served on ‘all the persons interested in, or having power to sell and convey or release, the land, so far as known to the acquiring authority after making diligent inquiry’. A notice to treat cannot be served on an unknown owner. However, where an owner remains unidentified ‘after making diligent inquiry’, CPA 1965, s 5(3) provides that CPA 1965, Sch 2 applies. CPA 1965, Sch 2 sets out the procedure for the payment of compensation where the owner of the land subject to compulsory purchase is absent or untraced. It should be noted that there are considerable advantages in using general vesting declaration as an alternative to the notice to treat, where ownership is not known, but the comparative